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Smoke on aerobatics with view of spade

Im sure everyone else knows that the spade is for but I dont. It was fun watching it move but what is the purpose? Cool video.
 
rockwoodrv9 said:
Im sure everyone else knows that the spade is for but I dont. It was fun watching it move but what is the purpose? Cool video.
Click to expand...

It's to lighten the stick forces at full deflection (like when doing rolls). It also helps with more crisp and precise starting and stopping of rolls.

Adding spades was the single best mod I've done on the plane to improve feel. It feels amazing now! Almost as light as a Pitts S2A at full deflection. And the crispness is also dramatically improved. Around center, not too much of a difference.
 
Spades

I can tell you from direct experience that Van does not like full deflection rolls in the RV4 and it is likely the same for other aerobatic RV's.
 
jrs14855 said:
I can tell you from direct experience that Van does not like full deflection rolls in the RV4 and it is likely the same for other aerobatic RV's.
Click to expand...

Would you care to expand on this please?
The mild aerobatic capabilities of certain RV's are a big part of the appeal for some and it would be a shame to discover that we can't/shouldn't use the flight controls to the maximum.
Thanks
 
Nice video! Did you make the spades yourself or did you buy a kit? I haven’t seen that option talked about much.
 
cool camera angle. I normally don't like MTV style rock videos (except the Van Halen one with the Blue Angles when i was a kid) but yours sorta worked for what it was.
 
Cool video Brian. Your 4 has changed significantly from when you first bought it. Love the green color. So unique. Beautiful.

Are you still competing in aerobatic events? If so what class?
 
Chkaharyer99 said:
Cool video Brian. Your 4 has changed significantly from when you first bought it. Love the green color. So unique. Beautiful.

Are you still competing in aerobatic events? If so what class?
Click to expand...

Thanks! Yes, it's almost a completely different plane than when I bought it. I added fuel injection, electronic ignition, about to do a major panel upgrade, experimented with 4 different props, added electric elevator trim, played with engine thrust angles, and a bunch of other things I don't even remember anymore.

I LOVE the way it flies now. Super light and responsive on the controls - more so than a handful of other RV's I've flown. The only thing I would want now is more power (200hp would be just about right), and fastback.

I practice the sequences for Sportsman and put together a free sequence every season, but never went to a contest after my first two contests in Primary. What I enjoy most is putting together fun "freestyle" sequences in which I'll do higher level stuff found in Intermediate or even Advanced. Of course they don't follow any of the rules, so it's just for my own entertainment and not contest flying.
 
I need to look up your back posts.. what did you do for electric trim? Servo in the elevator like an -8? Or remote mounted?
 
Look fun man. I just wouldn’t do any mods like that unless vans approved it or there were many other planes flying with them safely for many years.
 
Move on.

Hey Brian,
Nice work with the spades and other RV-4 mods. And don't let the naysayers hold you back. This is experimental aviation and careful, thoughtful modifications are the name of the game. The same naysayers would have had a fit when Van developed the RV-1 from a Stits Playboy. I worked with Van on his article on "RV Aerobatics" (EAA Magazine, August, 2016, attached below) and he initially had reservations about me doing snap rolls in my RV-8. When I described the way I worked up to them while staying well within the recommended G and speed limitations he relented and stated in the article that snap rolls are OK in the hands of experienced aerobatic pilots.

When I developed a mod that added lead shot to a box between the horizontal stabilizer front and rear spars to adjust the CG for aerobatics the noise from the naysayers was as if I had developed a kamikaze version of the RV. Turned out to be the best mod I ever made!

I hope you get back into competition. There is a noticeable lack of RV's in IAC events lately and we need to change that. Press on and good luck.
 

Attachments

  • IAC Aerobatics in RVs Rev A.pdf
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Sparrowhwk said:
Would you care to expand on this please?
The mild aerobatic capabilities of certain RV's are a big part of the appeal for some and it would be a shame to discover that we can't/shouldn't use the flight controls to the maximum.
Thanks
Click to expand...

I experience aileron buffeting at full deflection and some report that increasing deflection beyond buffeting does not increase roll rate. But perhaps the spades change that?

Finn
 
Spades

There is absolutely no need for spades for the type of acro done with an RV. You are motivating people to experiment in areas that could result in the ultimate penalty.
The shape of the trailing edge determines the control force on most all small, relatively low speed airplanes.
Concave trailing edge= heavier forces
Convex trailing edge+ light forces
Too much convex+ no centering force.
Look at any King Air 200/300 series ailerons. You will find a convex add on to the trailing edge of the ailerons for the purpose of lightening control forces.
 
FinnFlyer said:
I experience aileron buffeting at full deflection and some report that increasing deflection beyond buffeting does not increase roll rate. But perhaps the spades change that?
Click to expand...

I can't comment about the effect of aileron spades, but I've flown and instructed in all the two seat RVs except the -14, and they all exhibit the aileron buffeting you describe when fully deflected.

I've never found it objectionable, but it's interesting how little you need to move the stick off the stop to feel the buffeting disappear.

--Ron
 
FinnFlyer said:
I experience aileron buffeting at full deflection and some report that increasing deflection beyond buffeting does not increase roll rate.
Click to expand...
Since the buffeting is the aileron stalling, that's not surprising. In fact, you should find that reducing aileron deflection to just the point before buffeting starts should increase the roll rate from the buffeting state.
 
FinnFlyer said:
I experience aileron buffeting at full deflection and some report that increasing deflection beyond buffeting does not increase roll rate. But perhaps the spades change that?

Finn
Click to expand...
As I understand it, the spades are doing two things - lightening the stick forces and imparting a rolling moment on the airframe. With the buffet of the RV ailerons at ~~80-90% deflection, the spades are adding additional rolling moment component through the entire range of motion.

Interesting experiment. Thanks for sharing.
 
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Taltruda said:
I need to look up your back posts.. what did you do for electric trim? Servo in the elevator like an -8? Or remote mounted?
Click to expand...

It's the Ray Allen tri servo, mounted on the left side of the fuse. There was a cable that ran along the inside of the fuselage for the manual trim. I cut the cable there and attached the end to the trim servo. I'll take a picture for you when I go to the hangar later this week.
 
ronschreck said:
Hey Brian,
Nice work with the spades and other RV-4 mods. And don't let the naysayers hold you back. This is experimental aviation and careful, thoughtful modifications are the name of the game. The same naysayers would have had a fit when Van developed the RV-1 from a Stits Playboy. I worked with Van on his article on "RV Aerobatics" (EAA Magazine, August, 2016, attached below) and he initially had reservations about me doing snap rolls in my RV-8. When I described the way I worked up to them while staying well within the recommended G and speed limitations he relented and stated in the article that snap rolls are OK in the hands of experienced aerobatic pilots.

When I developed a mod that added lead shot to a box between the horizontal stabilizer front and rear spars to adjust the CG for aerobatics the noise from the naysayers was as if I had developed a kamikaze version of the RV. Turned out to be the best mod I ever made!

I hope you get back into competition. There is a noticeable lack of RV's in IAC events lately and we need to change that. Press on and good luck.
Click to expand...

Thanks Ron. I'm actually not the first to add spades to an RV4. I read about it in an article, that if I'm not mistaken, either you or Bill (Willieeyeball) sent or posted. Can't remember exactly. It was that RV4 that had the extended ailerons where he got rid of the flaps. Or am I mistaken?? My spades have been on for 2 years and over 200 hours, with at least 1/3 of those hours doing aerobatics. When I first put them on, I slowly and methodically increased speed up to 210mph and no signs of flutter or any other issues.

I also bought some lead and was thinking of a secure way of adding it to the tail for better balance while doing aerobatics! But I have lost so much weight from the nose and with my smoke tank in the rear, I'm close enough to a neutral CG now that I won't bother with the lead weight anymore. Figuring out a way to put it on and remove easily is a challenge. Also FORGETTING to remove and taking a passenger/ luggage would be a BIG problem, so I scratched that idea.
 
jrs14855 said:
There is absolutely no need for spades for the type of acro done with an RV. You are motivating people to experiment in areas that could result in the ultimate penalty.
The shape of the trailing edge determines the control force on most all small, relatively low speed airplanes.
Concave trailing edge= heavier forces
Convex trailing edge+ light forces
Too much convex+ no centering force.
Look at any King Air 200/300 series ailerons. You will find a convex add on to the trailing edge of the ailerons for the purpose of lightening control forces.
Click to expand...

Yes, you can optimize stick forces by playing with the trailing edge. But this affects stick forces near center, NOT at full or close to full deflection. When not at full or close to full deflection there is no need to lighten stick forces that much more anyway. The spades helped primarily to lighten stick forces near full deflection VERY substantially. I would almost say dramatically. Before, right rolls especially were heavy and almost required two hands. Now, I can roll either direction, even continuous rolls with just one hand and little effort. That's what I wanted. Also, starting and stopping rolls crisply (like while doing point rolls) is much better now.

If you don't do a lot of rolls or don't care about how it feels when you roll, then the spades are not necessary.
 
1flyingyogi said:
Thanks Ron. I'm actually not the first to add spades to an RV4. I read about it in an article, that if I'm not mistaken, either you or Bill (Willieeyeball) sent or posted. Can't remember exactly. It was that RV4 that had the extended ailerons where he got rid of the flaps. Or am I mistaken??
Click to expand...

Here's the article you were referring to:


 
Wonder where it is now

…I remember that article well ….pretty sure +/- 6 G was published limit on RV4 originally ( NOT suggesting anyone ignore the current published G limits that VANS provides) ….wonder what happened to the plane ?
 
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