Can anyone help me? I am in a position to purchase a Hartzell constant speed prop at a bargain price. The model is C2YK-1BF / F7666A-2. This prop is 74" in diameter and is 2 inches longer than most props going on a RV6A. I would like to put this prop on a Lycoming clone IO -360 180 hp engine. Can any one see any problems with this combonation? Would I be better off reducing the prop by 2 inches? Any advice would be appreciated. Cheers.
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Hartzell prop advice?
- Thread starter rv6ehguy
- Start date
gmcjetpilot
Well Known Member
Go for it
Big deal? Not in my opinion, but I am no RV6A expert. I recall people saying they had about +9" clearance. There are "A" models flying around with 74 incher's.
What does less clearance mean? Might pick up more small rocks and pebbles if you do run ups on ramps with small rocks and pebbles. Solution don't run up on ramps with small rocks and pebbles.
Soft field with lots of ruts, divots, holes, ridges, large molehills and super soft................. I would not go in there in a RV taildragger. Seriously you are giving up a tad of ground clearance and more soft field caution is in order. But a nice fairly flat firm "turf" or "soft-field" (not too soft) will be fine.
Close counts in horse-shoes, hand-granates and prop clearance. More the merrier but a good deal is a good deal.
Pilot technique. If you really blow it and smash the nose wheel into the runway from a botched landing, high bounce or PIO (pilot induced oscillation-porpoise) on landing than you'll have problems with any prop. In your case your problem will start 1 " earlier. If you hit your prop on landing you probably bent at least the gear.
74" will give you great climb and may be a mph less top speed at most. Also if you "touch" the the tip and damage it, you will have rework material. 72" is the official minimum diameter. You can go slightly under 72" buts its not approved, tested or a great idea.
Well you have 1" less ground clearance. You will be fine, however you will have 1" less clearance.rv6ehguy said:
Big deal? Not in my opinion, but I am no RV6A expert. I recall people saying they had about +9" clearance. There are "A" models flying around with 74 incher's. What does less clearance mean? Might pick up more small rocks and pebbles if you do run ups on ramps with small rocks and pebbles. Solution don't run up on ramps with small rocks and pebbles.
Soft field with lots of ruts, divots, holes, ridges, large molehills and super soft................. I would not go in there in a RV taildragger. Seriously you are giving up a tad of ground clearance and more soft field caution is in order. But a nice fairly flat firm "turf" or "soft-field" (not too soft) will be fine.
Close counts in horse-shoes, hand-granates and prop clearance. More the merrier but a good deal is a good deal.
Pilot technique. If you really blow it and smash the nose wheel into the runway from a botched landing, high bounce or PIO (pilot induced oscillation-porpoise) on landing than you'll have problems with any prop. In your case your problem will start 1 " earlier. If you hit your prop on landing you probably bent at least the gear.
74" will give you great climb and may be a mph less top speed at most. Also if you "touch" the the tip and damage it, you will have rework material. 72" is the official minimum diameter. You can go slightly under 72" buts its not approved, tested or a great idea.
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Captain Avgas
Well Known Member
gmcjetpilot said:
It's the same on the RV7s...people keep advocating the 74" Hartzell prop because "they'll have some spare metal in the case of a prop strike". But it's probably a false logic. It also probably appeals to those who feel they might be getting something for nothing (an extra inch of aluminium).
If the prop can be repaired by removing less than 1" of the tip then it is a VERY minor strike and it is therefore highly probable that less than 1" of the tip was involved in the strike. In other words, given the same circumstances, there would have been NO prop strike if a 72" prop was being used.
Personally I plan on going 72" to obtain the max clearance I can get. If I strike the 72" prop then my insurance company is going to have to buy me a new prop rather than repair the old one.....that's good.
Performance aside, when it comes to props....less is more.
But if in your case it's a really terrific deal...then that's a factor.
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I hope you are not referring to my prop choice here (IVO)
I'm feeling pretty good that I don't have a Hartzell with 100 hour inspections or a WW with scary blade problems right now. Once a year, I remove spinner and check the 6, 1/2 inch bolts that hold the blades on for torque. Replace spinner. Done. Whole prop new cost me $1700.
A friend here does flight training with Rotax powered aircraft fitted with the much maligned IVO also. He has over 2500 hours on his with zero issues. Can't be half bad.
I hope my certified MT works this well on the RV10.
I'm feeling pretty good that I don't have a Hartzell with 100 hour inspections or a WW with scary blade problems right now. Once a year, I remove spinner and check the 6, 1/2 inch bolts that hold the blades on for torque. Replace spinner. Done. Whole prop new cost me $1700.
A friend here does flight training with Rotax powered aircraft fitted with the much maligned IVO also. He has over 2500 hours on his with zero issues. Can't be half bad.
I hope my certified MT works this well on the RV10.
phil9diesel
Active Member
prop chop
Think of trimming your Hartzell like staining your hardwood floors dark dark brown. Devaluated. If I came across a beautiful metal prop too long for my plane, I'd leave it for someone who could use it. Just a little long and everything works? Use it. Don't punch the gas when you start your run. That's how props get knicks. A prop 1 inch too long will work nice at altitude.
Think of trimming your Hartzell like staining your hardwood floors dark dark brown. Devaluated. If I came across a beautiful metal prop too long for my plane, I'd leave it for someone who could use it. Just a little long and everything works? Use it. Don't punch the gas when you start your run. That's how props get knicks. A prop 1 inch too long will work nice at altitude.
gmcjetpilot
Well Known Member
The evils of Lycoming
Yea you know Ross the evil Lycoming's power pulse that is devilishly harsh on props compared to a smooth running Rotax or Subie that the IVO can't handle.rv6ejguy said:I hope you are not referring to my prop choice here (IVO)
A friend here does flight training with Rotax powered aircraft fitted with the much maligned IVO also. He has over 2500 hours on his with zero issues. Can't be half bad.
DCalland
Member
Hartzell prop
I had the same question about which prop to get. Hartzell recommended the 74" because it can be serviced down to 72" over the life of the prop if needed. The 72" prop cannot be serviced shorter with overhauls. I just picked my prop up a few weeks ago but it is not installed yet.
N980DC reserved
RV7-A quickbuild in slow mode
I had the same question about which prop to get. Hartzell recommended the 74" because it can be serviced down to 72" over the life of the prop if needed. The 72" prop cannot be serviced shorter with overhauls. I just picked my prop up a few weeks ago but it is not installed yet.
N980DC reserved
RV7-A quickbuild in slow mode
Captain Avgas
Well Known Member
DCalland said:
A need to shorten the diameter of a prop during normal servicing or overhauls is virtually unheard of. The only thing that is likely to lead to a shortening is a prop strike of some sort. And it is highly unlikely that a prop strike could be repaired by removing just 1".
I think the salient issue for the original poster is ground clearance. Don't forget that you have a 7 and he has a 6.....there's probably different ground clearance involved.
I see a lot of posts here...but no-one is putting actual figures on ground clearance which is the most important factor. For instance if you have +12" of ground clearance then you may as well go for a 74". But if you're down to 8" of clearance it may well make better sense to go with a 72".
Then there's the consideration of landing surfaces. On hard surfaces you don't need the clearance you need on soft surfaces, so the type of strips you intend to land on should also be a factor.
Builders should not be seduced by the warm and fuzzies of having an extra inch of metal to trim back (that in all probability they will never need). Initial ground clearance is THE bottom line.
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The original poster has a 6A which I also have and with a 76 inch prop, I think I have about 7.5 inches of ground clearance with nobody aboard and have had no issues with picking up rocks. That being said, my airplane has never seen grass strips. The 7A has a much more level ground stance and it seems as though the main gear is longer to me which might give you a bit less prop clearance than on the 6A.
Don't think a 74 inch is anything to worry about on a 6A.
Don't think a 74 inch is anything to worry about on a 6A.
I know of one RV-6 that had a 74 inch prop. The builder sold it after flying around 200 hours with no problems. The new owner was doing transition training (with an RV pilot / CFI) in it and hit the prop on a wheel landing during the first two hours.rv6ehguy said:
