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My RV7A needs a diet..

Dandlac58

Well Known Member
Super Tweety, my 2004 RV7A is a pretty girl, but she's big boned and "carrying a little extra"!

Just did a new weight and balance and she tipped the scales at 1203 empty weight. meaning only 597 useable. I guess you could say "pigs can now fly"!! :)

Not a lot of places to cut weight... but looking at lithium ion batteries, specifically EarthX ETX 680 to replace my Odyssey PC680. The EarthX delivers more performance and can withstand temps higher than the Odyssey 170 to 113 degrees respectively. Significantly, the EarthX is 11 pounds lighter than the Odyssey and smaller in form. EarthX also has a "thermal battery box" for an additional $115!

I'm thinking about using temperature stickers to see how hot it is actually getting where the battery is installed in the engine compartment - upper left firewall as you look at the airplane.

Does anyone have experience to share on the EarthX Li Ion with Battery Management System? Or something similar?

One of my buddies on here, who shall remain nameless, but with whom I give great respect... says the Li Ion batteries are not ready for prime time...

Also, any thoughts, reasonable, rational thoughts that is.... on getting Tweety a weight loss of about 40-50 pounds?

Thanks in advance for any knowledge and experience shared.

Dan
 
We’ve had two EarthX batteries and they’ve been fantastic, although the location is in the cabin.

As for weight, take the prop off and replace with Catto, take the instruments out and replace with a J-3 hand out, scrub the paint off and polish it, convert to tailwheel and ditch the heavy nose gear, replace the seats and interior with a gel pad from Walmart, and maybe downsize the engine to a 320 while you’re at it. That ought to lighten things up a bit! Now since you’re not going to do any of those, I’d say enjoy flying that pig!!!
 
Really?

First off, are you sure your scales are correct? I mean, I have an RV-7 that's on the heavy end of the spectrum, as it has paint with clear coat, leather interior with side panels, autopilot, and all the bells and whistles I wanted (or at least thought I wanted). And it's still way below what you're quoting. So before you get too depressed, I'd verify that your scales are correct and that you're measuring it correctly (i.e., only unusable fuel in the tanks, level attitude, etc.).

Regarding the lithium battery, opinions are all over the place on that. It's kind of like the "primer wars" and any of the myriad debates that take place within this forum and during hangar flying sessions. Call up EarthX and talk to the lady there. She's very knowledgeable and can probably answer many of your questions.

I replaced my PC-680 with the EarthX ETX 680, and I think it saved something like twelve pounds using their standard aluminum mounting box on the firewall. Connecting the BMS lead to the EFIS was pretty simple, as the discrete input wire was already in the harness for my Garmin G3X from SteinAir. After that, it was just a configuration setting in the Garmin, and EarthX gives guidance on how to do that. And as I recall, the batteries are less susceptible to heat than the usual batteries that are commonly used.

As far as shedding weight...if Tweety truly is that heavy, it can be done. You'll have to take a hard look at what your typical mission is, how much redundancy you need, and what superfluous items you have. That can be as big as a total avionics gut & upgrade, an interior rebuild, or it may just be a selective pruning of dead weight items that were installed and no longer needed. Did you build it? Do you know what all is in there?

I'm sure the naysayers are going to jump all over this, but all I can give you is my experiences and my opinions.
 
Reasonable and Rational!!! :)

Hey Oakland - you forgot the reasonable and rationale qualifier - you are 100% correct that Im not doing any of those things!!! But thanks for the info on your EarthX batts!

My little piggie still scoots along at 175 knots at 24x24.

We’ve had two EarthX batteries and they’ve been fantastic, although the location is in the cabin.

As for weight, take the prop off and replace with Catto, take the instruments out and replace with a J-3 hand out, scrub the paint off and polish it, convert to tailwheel and ditch the heavy nose gear, replace the seats and interior with a gel pad from Walmart, and maybe downsize the engine to a 320 while you’re at it. That ought to lighten things up a bit! Now since you’re not going to do any of those, I’d say enjoy flying that pig!!!
 
Similar pigs!!

Hi Dubya

We were careful during the Weight and Balance - emptied every drop of fuel and everything not screwed, bolted or welded on. Level attitude. So she was truly at empty weight (oh and there were 8 quarts of oil in the crankcase.) A&P has certified scales. So I feel like the weight we got is accurate.

Mine sounds a lot like yours, IO-360 with all bells and whistles, Hartzell Constant speed prop, autopilot, GNS430W, SL40, GTX327, GRT EFIS and EIS, two emag ignitions, full paint and clear coat, primary and back up lead acid batteries, and a Pro G Hub and cables connecting all the avionics together. Full interior, cloth not leather. Has both sets of mounting points for nose or tail gear configurations so there is some extra weight there.

I did talk to Kathy at EarthX and she was extremely helpful... just wanted to get thoughts from the field as to what they have found using the batteries. Its a quick way for me to lose 15 pounds by replacing the main Odyssey (15.9 lbs) and backup (5.1 lbs) Lead Acid batteries with one LI ION, 4.1 lbs.

And of course I could lose 10 pounds to get to "Standard Pilot" weight of 170!

How much does your bird weigh?

Thx
Dan

First off, are you sure your scales are correct? I mean, I have an RV-7 that's on the heavy end of the spectrum, as it has paint with clear coat, leather interior with side panels, autopilot, and all the bells and whistles I wanted (or at least thought I wanted). And it's still way below what you're quoting. So before you get too depressed, I'd verify that your scales are correct and that you're measuring it correctly (i.e., only unusable fuel in the tanks, level attitude, etc.).

Regarding the lithium battery, opinions are all over the place on that. It's kind of like the "primer wars" and any of the myriad debates that take place within this forum and during hangar flying sessions. Call up EarthX and talk to the lady there. She's very knowledgeable and can probably answer many of your questions.

I replaced my PC-680 with the EarthX ETX 680, and I think it saved something like twelve pounds using their standard aluminum mounting box on the firewall. Connecting the BMS lead to the EFIS was pretty simple, as the discrete input wire was already in the harness for my Garmin G3X from SteinAir. After that, it was just a configuration setting in the Garmin, and EarthX gives guidance on how to do that. And as I recall, the batteries are less susceptible to heat than the usual batteries that are commonly used.

As far as shedding weight...if Tweety truly is that heavy, it can be done. You'll have to take a hard look at what your typical mission is, how much redundancy you need, and what superfluous items you have. That can be as big as a total avionics gut & upgrade, an interior rebuild, or it may just be a selective pruning of dead weight items that were installed and no longer needed. Did you build it? Do you know what all is in there?

I'm sure the naysayers are going to jump all over this, but all I can give you is my experiences and my opinions.
 
We’ve been flying with an EarthX on the firewall of our Tundra for about five years with no problems or difficulties. The FAA Considers them “ready for prime time”, having certified them for use on commercially produced aircraft. They’ve got a dual BMS architecture to keep them safe, and you need to understand that could mean that the battery turns itself off to keep IT safe - so a backup is a good idea if loss of battery is critical in your operation.

I don’t hesitate to fly with them.

Paul
 
Avionics and wiring are pretty heavy. When Walt redid my panel and weighted the airplane he pulled out 40lbs of gyros, autopilot servos, and old wiring…it adds up quick.
 
I put my -4 on a diet with an EarthX battery (love it!) in lieu of the Concorde gel cell, an AHRS is in lieu of the vacuum system, and a Titanium tail spring in lieu of the original steel version. I gave up some of the savings in order to go from 0.016 to 0.020 elevator and rudder skins. Soon I will get new paint w/o the clear coat this time, and will re-weigh the aircraft. You will see the biggest gains with an EarthX battery and a composite prop, assuming you don't already have one. After those things, further weight savings will get expensive quickly...

Good luck
 
thought about the X, but a definite no now… a story about a certain RV-8 having to partially open it’s canopy to let billowing smoke out for an emergency landing :eek:
In the engine compartment, maybe…

PS
Don’t ask for details, thanks
 
Hi Paul.
Thanks for your input on the EarthX LI Ion. 5 years of solid performance says a lot and I appreciate it. I do understand about the BMS potentially turning off the battery to save it from over voltage situation - but you have yet to experience that situation in 5 years? What alternator do you have on your bird? I also understand I need to put an Overvoltage Protection Device like Olsen Technologies to spare the Avionics too. Im liking the EarthX more and more as I discover more info about them. They appear to be a great way to boost power and really take some weight off.
Dan


We’ve been flying with an EarthX on the firewall of our Tundra for about five years with no problems or difficulties. The FAA Considers them “ready for prime time”, having certified them for use on commercially produced aircraft. They’ve got a dual BMS architecture to keep them safe, and you need to understand that could mean that the battery turns itself off to keep IT safe - so a backup is a good idea if loss of battery is critical in your operation.

I don’t hesitate to fly with them.

Paul
 
Dan
That's a concern for sure... it will not go in the cockpit and Im going to first apply some temperature stickers to get a better understanding of the heat in the engine compartment where the battery would go... I will also route some blast air ducts to the battery and use their insulated battery box if I decide to make the move.
Thanks for your thoughts.


thought about the X, but a definite no now… a story about a certain RV-8 having to partially open it’s canopy to let billowing smoke out for an emergency landing :eek:
In the engine compartment, maybe…

PS
Don’t ask for details, thanks
 
Thanks Dean for your thoughts on the EarthX, surely helps me understand the EarthX as being a solid option. Do you use the ETX680?

Thanks
Dan

I put my -4 on a diet with an EarthX battery (love it!) in lieu of the Concorde gel cell, an AHRS is in lieu of the vacuum system, and a Titanium tail spring in lieu of the original steel version. I gave up some of the savings in order to go from 0.016 to 0.020 elevator and rudder skins. Soon I will get new paint w/o the clear coat this time, and will re-weigh the aircraft. You will see the biggest gains with an EarthX battery and a composite prop, assuming you don't already have one. After those things, further weight savings will get expensive quickly...

Good luck
 
Hi Rhino,
I agree, and I think the Pro G Hub and all the cables they fabricated for my configuration added some serious weight to my avionics suite.

Avionics and wiring are pretty heavy. When Walt redid my panel and weighted the airplane he pulled out 40lbs of gyros, autopilot servos, and old wiring…it adds up quick.
 
Thanks Dean for your thoughts on the EarthX, surely helps me understand the EarthX as being a solid option. Do you use the ETX680?

Thanks
Dan

Hi Dan,

I just checked my records. I purchased the ETX900 at the recommendation of the EarthX folks and installed it in November of 2016. It charges at approximately 14.3 volts on my alternator/regulator set-up (no changes from my original lead-acid set-up). It rarely sits for more than a week, but even during annual, it never drops below 13.1 volts (no load). The engine starts much better with this battery (as compared to the Concorde battery). I attribute the better performance to the reduced voltage drop. My PMags like to be around 12 volts. If the voltage droops much during cranking, my engine wouldn't catch until I released the starter button and the voltage recovered a bit. No such issue with the EarthX. In my -4, the battery is mounted between my feet. A common location in a -4, though there is lots of room for debate whether that is the best place for it.

Good luck,

Dean
 
Great Info Dean,
Thanks for digging through your records, I sure appreciate it, I like your info on engine start and Ive heard from others too about how the batteries hold their charge for long periods.
Dan

Hi Dan,

I just checked my records. I purchased the ETX900 at the recommendation of the EarthX folks and installed it in November of 2016. It charges at approximately 14.3 volts on my alternator/regulator set-up (no changes from my original lead-acid set-up). It rarely sits for more than a week, but even during annual, it never drops below 13.1 volts (no load). The engine starts much better with this battery (as compared to the Concorde battery). I attribute the better performance to the reduced voltage drop. My PMags like to be around 12 volts. If the voltage droops much during cranking, my engine wouldn't catch until I released the starter button and the voltage recovered a bit. No such issue with the EarthX. In my -4, the battery is mounted between my feet. A common location in a -4, though there is lots of room for debate whether that is the best place for it.

Good luck,

Dean
 
Gyros?

Do you have conventional gyro instruments? They are surprisingly heavy. Something like a Garmin G5 or Dynon D10a / D6 can shed a few pounds.

Sound deadening material can really add up quick as well.

Did the brake pedals get lightening holes?
How about the PC 680 battery box?

Conventional Strobe power pack?

LED landing lights or conventional reflector bulbs?
 
Hi Blaplante,

No Conventional Gyros, I have a GRT EFIS which provides, 6 pack, engine monitoring, and navigation all on one screen. I do have a back up attitude gyro but it is electric driven.

PC680 box is aluminum and minimal.

Brake pedals have holes. I do have sound deadening material and I know its extra weight, but dont want to give it up.

I do have LED Landing lights.

Yes, I do have a conventional Strobe power pack behind the rear bulkhead wall. And it looks like a heavy device although I dont know it's weight. What is your recommendation for replacing it?

I also have an old style 121.5 ELT with 6 D Cell batteries also mounted on the inner belly behind the rear bulkhead.

Thanks for your thoughts, I appreciate it.

Dan


Do you have conventional gyro instruments? They are surprisingly heavy. Something like a Garmin G5 or Dynon D10a / D6 can shed a few pounds.

Sound deadening material can really add up quick as well.

Did the brake pedals get lightening holes?
How about the PC 680 battery box?

Conventional Strobe power pack?

LED landing lights or conventional reflector bulbs?
 
I recently swapped my Hartzell BA for an MT which saved about 8 lbs, changed my BU alt from B&C to Monkworkz cut 3 lbs, changed BU battery from PC310 to TCW cut 3 more lbs.

I also raised my GW to 1900# long ago so I would stay legal when going to Osh. :eek:
 
Hi Blaplante,

I do have a back up attitude gyro but it is electric driven.

PC680 box is aluminum and minimal.


Yes, I do have a conventional Strobe power pack behind the rear bulkhead wall. And it looks like a heavy device although I dont know it's weight. What is your recommendation for replacing it?


Thanks for your thoughts, I appreciate it.

Dan

Electric Gyros are suprisingly heavy. You could put in a dynon D3 and drop around 2 pounds.

My PC680 box is steel. Surprised yours is aluminum.

Whelen Strobe packs vary a good bit in weight. I have an older model that weighs at least a pound more than a newer model. I'm talking aircraft grade packs... But the newer one takes more amps and I'd need to run new wire.

Do you have conventional mags?
Swapping one for a lightspeed (for example) will drop pounds.
 
How does one go about changing the GW?

Hi Walt,

You just mentioned something of which I was not aware. How do you go about changing the GW of your airplane? Must you be the builder (I am not)? That's a really nice way of gaining 100 lbs of useable load - as long as I dont create an unflyable airplane in doing so...

Thanks
Dan

I recently swapped my Hartzell BA for an MT which saved about 8 lbs, changed my BU alt from B&C to Monkworkz cut 3 lbs, changed BU battery from PC310 to TCW cut 3 more lbs.

I also raised my GW to 1900# long ago so I would stay legal when going to Osh. :eek:
 
Saving weight always costs $$$ and sometimes effort and a few hours of work. I am in the process of trying to save 70lb from an RV-6 and have found it helps to set a budget for $$/lb. Anything over $200/lb is definitely not worth it and I hope many of the things I have done work out cheaper. A lithium battery is pretty good value, around $50/lb. I have also fitted a Whirlwind carbon prop saving 25lb, depends how much I sell my Hartzell for as to final $$/lb - might be pushing the $200 limit but difficult to save 25lb elsewhere. Much of the weight saving is from a few lb here and there. Throwing out the old strobes saves around 4lb, including 1 or 2 lb of strobe wire. LED landing lights draw much less current and can tolerate thinner wiring. P-Mags save 3 or so lb. A light weight starter can help, depending on what you are currently running. There is always the risk of the CG moving aft so needs watching. It is much easy to save lb forward of the firewall, and can be quite costly. Ensure your scales are accurate and understand the impact of every change made.
Pete
 
D3, etc

Blaplante,

It has Emag Ignition's P-114 electronic ignition on both sides. It also has a light weight starter, the name of which escapes me at this moment.

The Dynon D3 is not a bad idea or maybe the G5, the D3 is quite a bit less expensive at $899 compared to $1420 for the experimental G5. I had a G5 in my Cherokee and it was a really nice 6 pack. Does the D3 need a GPS source? Oooops, followup, does not need a GPS source, just put its antenna on the dashboard.

I do not know which strobe pack I have but next time Im behind the bulkhead I will find out... it's a fairly large sized box, I know that. Previous owner did not do a great job of documenting his airplane so I find myself doing it now. Lesson learned! She's a good bird though, just portly! :)

I love the Hartzell constant speed prop... dont think I can give it up!!

Thanks

Dan

Electric Gyros are suprisingly heavy. You could put in a dynon D3 and drop around 2 pounds.

My PC680 box is steel. Surprised yours is aluminum.

Whelen Strobe packs vary a good bit in weight. I have an older model that weighs at least a pound more than a newer model. I'm talking aircraft grade packs... But the newer one takes more amps and I'd need to run new wire.

Do you have conventional mags?
Swapping one for a lightspeed (for example) will drop pounds.
 
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All good thoughts....

Pete,

Good thoughts. The previous owner spent quite a bit on Super Tweety and I was the lucky recipient when he sold it to me - although I did pay a pretty penny for her too. But Tweety was set up more for luxury, situational awareness and redundancy than for GW - all things which I appreciate!
I'm liking the EarthX battery the more I read about it and it is a great way to save some serious weight especially if I drop the small backup battery too - the savings is then over 15 pounds. The other way, which I am far less enthusiastic about, is the pilot dropping 10 pounds! I cant really lose either leg or either arm, so it is one head or the other, and that's not a great option either... perhaps a butt cheek!?? :) (Of course I could try to find a lighter co-pilot, oops - I didnt say that!)

So I guess it is me and the batteries for 25 lbs! Perhaps my backup electric Gyro for a D3 (expensive weight loss)

Dan

Dan


Saving weight always costs $$$ and sometimes effort and a few hours of work. I am in the process of trying to save 70lb from an RV-6 and have found it helps to set a budget for $$/lb. Anything over $200/lb is definitely not worth it and I hope many of the things I have done work out cheaper. A lithium battery is pretty good value, around $50/lb. I have also fitted a Whirlwind carbon prop saving 25lb, depends how much I sell my Hartzell for as to final $$/lb - might be pushing the $200 limit but difficult to save 25lb elsewhere. Much of the weight saving is from a few lb here and there. Throwing out the old strobes saves around 4lb, including 1 or 2 lb of strobe wire. LED landing lights draw much less current and can tolerate thinner wiring. P-Mags save 3 or so lb. A light weight starter can help, depending on what you are currently running. There is always the risk of the CG moving aft so needs watching. It is much easy to save lb forward of the firewall, and can be quite costly. Ensure your scales are accurate and understand the impact of every change made.
Pete
 
Another idea: Lightweight Flywheel?
Not a cheap option. Can save a pound.

Note that the Dynon D3 uses GPS for altitude and airspeed. If the main purpose is as a attitude gyro in a crunch (and you have another backup altitude/airspeed) then that may be OK.

OTOH, if you do have standby gyro, airspeed, and altimeter, consider ditching all of those for the G5.

Seriously go back and look at the sound deadening. I bought some, was going to install it until I figured out it was something like a pound for every 2 square feet! You may be able to swap to lighter stuff.
 
D3

It looks like the D3 gives you everything the G5 does (G5 without a magnetometer) and includes synthetic vision and a second page which is a G Meter. Pretty cool!

The Dynon weighs a massive 8 ounces! Im sure the electric gyro probably weighs 3-4 pounds. Pricey weight loss but get some nice redundancy and even some additional capabilities like G meter and synthetic vision. And since it has its own internal battery, no draw on the airplane so good in an electrical emergency. And once Im comfy with the D3 I could lose the steam airspeed and altimeter along with the electric attitude gyro. But I will keep them for awhile since I am a founding member of the Department of Redundancy Department....

Features: https://www.dynonavionics.com/pocket-panel.php#0

I like that the D3 can be pinched into the opening which would be created by pulling out the electric gyro.
 
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thought about the X, but a definite no now… a story about a certain RV-8 having to partially open it’s canopy to let billowing smoke out for an emergency landing :eek:
In the engine compartment, maybe…

PS
Don’t ask for details, thanks
I presume this relates to this incident: https://vansairforce.net/community/showthread.php?t=154336
It should be noted that in a follow-up post on the same thread, the author of the report (presumably the incident pilot or passenger) stated that:
The authors believe that the EarthX lithium-iron-phosphate battery behaves predictably and does okay in this incident relative to other battery types. This is particularly true considering the environment into which the EarthX battery was installed (no overvoltage protection, no warning light, no overboard vent), what happened in-flight, and what the battery was subjected to. The authors hope that their report leads to increased understanding of what is required to safely install and confidently fly EarthX (and other lithium-iron-phosphate) batteries as well as other battery types including lead-acid.
 
Excellent!!

Randall,

Thank you very much for sharing the link on the RV8 incident, extremely important report in all aspects.

Very clear that I will be installing over voltage protection ASAP and in advance of the purchase of the EarthX. And will definitely connect a warning LED from the BMS. Just too much expensive avionics not to take every precaution. Not to mention the airplane and my skin too!!

Is there a good known method for checking the voltage regulator and will it, by itself, prevent an over voltage situation or is it necessary to have something like the "crowbar" OVPD?

Thanks

Dan


I presume this relates to this incident: https://vansairforce.net/community/showthread.php?t=154336
It should be noted that in a follow-up post on the same thread, the author of the report (presumably the incident pilot or passenger) stated that:
 
OVP is included (and works) with the B&C regulator, would not trust the PP to do the same.
 
Mine weighed in a lot heavier than I wanted, and I decided the most cost-effective and straightforward way to address it is for me to hit the treadmill. :p
 
Yeah... me too... which means I have to cut ten pounds off my carcass. Ugh! The ETX 680 seems like a great way to lose another 15 pounds when I replace both of my lead acid with one of them. I'm hearing nothing but good things about it,with the assumption that you properly equip your airplane with OVPD to protect your battery and avionics.

Im also very much liking the idea of replacing my electric attitude gyro with a Dynon D3... but that's expensive at $900.00. But with the GRT EFIS and the D3, I can also eventually eliminate my airspeed and altitude steam devices too. The D3 is portable, weighs 8oz, and comes with synthetic vision and a G Meter as well. Nice!

Mine weighed in a lot heavier than I wanted, and I decided the most cost-effective and straightforward way to address it is for me to hit the treadmill. :p
 
Yes I have a LOT OF IDEAS as any long time forum members will say (and long winded).

THINGS YOU CAN'T FIX NOW

OK you don't say what engine and PROP you have. If you are ROCKING and Angle Valve Fuel Injected Lycoming and Metal Hartzell you can blame some of that on your engine prop combo. If you are rockng a O-320/O-360 with fixed wood prop, day/night VFR, painted, basic bare upholstery. You save A LOT OF WEIGHT with his configuration. Right. There is nothing you can do at this point about engine and prop realisticly. I guess if money no object REMOVE a metal prop for a composite prop.

Paint and Upholstery - If you have fancy paint, fancy cockpit upholstry you added weight, significant amount. A spartan basic bare interior and no paint you are going to be a lot lighter. A compromise is very light paint, one primer and one light top coat, no clear or multi layer paint. Nice seats and may be sime light carpet for a light interror. It is unlikely you will UNDO deluxe paint and upholstery. However look at your carpet and other DOOO-DADS that might be removed. You could strip the cockpit of all padding, carpet, side wall panels and leave just basic seats.***

PANEL - OK again it is unlikely you will want to remove these bells and whistles, but you might.If you never fly night remove night lights. If you never fly IFR and have heated pitot, remove that and all wiring. You could remove all the extra stuff and leave basic VFR.

THINGS YOU CAN DO

GO ON DIET -- I could stand to lose 30 t0 40 lbs. to get into fighting weight. Consider going on a diet if you have a few L-Bee's to lose.

When I got into RV's late 80's in the North West, Van was in business since 1973, over 12 yrs at that point. He had the RV-3 (1993) and RV-4 (1979) out and the RV-6 (1985) was BRAND NEW.... All of van's two place demo planes, the -4 and -6 were 320's with wood props. They flew great (I flew the RV-6 prototype with Van himself). I was lighter then and Richard "Van" is a bean poll. These planes fly AMAZING when light. It was not uncommon for RV's to be under 1000 lbs empty wt.

When they get heavy the RV magic is reduced. I have test flown both super light wood prop RV's and super heavy ones. I can say I enjoy light RV's best. However the power of IO360 and constant speed prop can off set the added weight. HOWEVER you have to be oh so careful to keep it as light as possible in every other area. Once the plane is finished it is hard to shave significant weight. The Subaru Eggenfellner planes were very heavy. Never flew one. Never will. Nothing you could do about that engine to fix weight.


***
A repair facility for large jet components, overhauled an Aileron for a MD-11. They did all required inspections, AD's and refinish flight control. All standard stuff. The aileron could not be balanced. Most flight controls are statically balanced to prevent flutter. No amount of balance weights would balance this aileron, without hitting the aircraft wing structure. You add metal plates and there is a physical and specified limit. To make it worse they use to use depleted uranium sealed in a coating. Those are a NO NO now. Well this repair facility hired a custom car painter. He gave it a custom paint job. I told them what to do. Strip the paint. The balance problem went away even after repainting with primer and one or two light coats.
 
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Mine weighed in a lot heavier than I wanted, and I decided the most cost-effective and straightforward way to address it is for me to hit the treadmill. :p

We just weighed in at 1189 lbs (with composite prop and earthx already). My only option left is to go on a diet and lose 30 lbs.
 
Got it backwards....

GO ON DIET[/B] -- I could stand to lose 30 t0 40 lbs. to get into fighting weight.

I am at my fighting weight.....I need to lose 30-40 lbs to get to get to the point where I can RUN AWAY from a fight ;)

L
 
6 of one half dozen of the other maybe? I’ve got a light airplane. 1014 lbs. RV-7, O-320, wood prop, single Dynon Skyview screen, synthetic leather seats and basic carpets, PC680. My useful load may be technically better than yours, but my performance will suffer. Having said that, with half tanks and single pilot on a cool day it’s pretty awesome.
 
Hi GMC,

I think the majority of my excess weight comes from the fact the airplane has mounting points for 7 and 7A configuration which Im guessing is adding 30 lbs - that I cannot change, perhaps will not change as it is a neat option which RVs do not have. It has two lead acid batteries totalling 20 lbs. That I can change and will change saving almost 15 pounds in the process. Not much else I can change as I like the bird the way she is set up for comfort, redundancy, and situational awareness, so that leaves me with the most uncomfy of all options getting dead weight off my carcass... Im 180, would love to get to 170... may be impossible because I sure like eating well! And I am good about exercise but it seems **** near impossible to lose weight anymore.

A couple of guys have told me how they increased their GW which is interesting... and not too difficult, the trade off being you need to keep fuel in the tanks to keep the CG in the envelope for landing. It's something to think about but having to keep 10 gallons of fuel in the tanks is not something I relish to be honest.

Dan

Another guy said you can ship some items if you are going on a trip with a long stay like EAA at Oshkosh... legitimate idea.

Yes I have a LOT OF IDEAS as any long time forum members will say (and long winded).

THINGS YOU CAN'T FIX NOW

OK you don't say what engine and PROP you have. If you are ROCKING and Angle Valve Fuel Injected Lycoming and Metal Hartzell you can blame some of that on your engine prop combo. If you are rockng a O-320/O-360 with fixed wood prop, day/night VFR, painted, basic bare upholstery. You save A LOT OF WEIGHT with his configuration. Right. There is nothing you can do at this point about engine and prop realisticly. I guess if money no object REMOVE a metal prop for a composite prop.

Paint and Upholstery - If you have fancy paint, fancy cockpit upholstry you added weight, significant amount. A spartan basic bare interior and no paint you are going to be a lot lighter. A compromise is very light paint, one primer and one light top coat, no clear or multi layer paint. Nice seats and may be sime light carpet for a light interror. It is unlikely you will UNDO deluxe paint and upholstery. However look at your carpet and other DOOO-DADS that might be removed. You could strip the cockpit of all padding, carpet, side wall panels and leave just basic seats.***

PANEL - OK again it is unlikely you will want to remove these bells and whistles, but you might.If you never fly night remove night lights. If you never fly IFR and have heated pitot, remove that and all wiring. You could remove all the extra stuff and leave basic VFR.

THINGS YOU CAN DO

GO ON DIET -- I could stand to lose 30 t0 40 lbs. to get into fighting weight. Consider going on a diet if you have a few L-Bee's to lose.

When I got into RV's late 80's in the North West, Van was in business since 1973, over 12 yrs at that point. He had the RV-3 (1993) and RV-4 (1979) out and the RV-6 (1985) was BRAND NEW.... All of van's two place demo planes, the -4 and -6 were 320's with wood props. They flew great (I flew the RV-6 prototype with Van himself). I was lighter then and Richard "Van" is a bean poll. These planes fly AMAZING when light. It was not uncommon for RV's to be under 1000 lbs empty wt.

When they get heavy the RV magic is reduced. I have test flown both super light wood prop RV's and super heavy ones. I can say I enjoy light RV's best. However the power of IO360 and constant speed prop can off set the added weight. HOWEVER you have to be oh so careful to keep it as light as possible in every other area. Once the plane is finished it is hard to shave significant weight. The Subaru Eggenfellner planes were very heavy. Never flew one. Never will. Nothing you could do about that engine to fix weight.


***
A repair facility for large jet components, overhauled an Aileron for a MD-11. They did all required inspections, AD's and refinish flight control. All standard stuff. The aileron could not be balanced. Most flight controls are statically balanced to prevent flutter. No amount of balance weights would balance this aileron, without hitting the aircraft wing structure. You add metal plates and there is a physical and specified limit. To make it worse they use to use depleted uranium sealed in a coating. Those are a NO NO now. Well this repair facility hired a custom car painter. He gave it a custom paint job. I told them what to do. Strip the paint. The balance problem went away even after repainting with primer and one or two light coats.
 
We just weighed in at 1189 lbs (with composite prop and earthx already). My only option left is to go on a diet and lose 30 lbs.

Im with you... Im at 180 and need to get to 170 but dang it is near impossible to lose weight anymore even though I am pretty religious about hitting the gym... Im just not a great calorie counter and I love good food!! :)

Dan
 
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