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F4 Wing Selection

DarinFred

Active Member
I'm in the process of planning an F4 build starting early next year. There are a few wing options that will work with the F4, mainly the Harmon modded RV-4 "sport" wing or RV-8 wing. With the RV-4 wing being more difficult to build, what other things should I consider when choosing between the Harmon modded RV-4 versus an RV-8 wing?

Thanks!
Jay
 
I'm in the process of planning an F4 build starting early next year. There are a few wing options that will work with the F4, mainly the Harmon modded RV-4 "sport" wing or RV-8 wing. With the RV-4 wing being more difficult to build, what other things should I consider when choosing between the Harmon modded RV-4 versus an RV-8 wing?

Thanks!
Jay

Wing loading. The second best thing about a rocket is the higher wing loading. I believe the modified 4 wing is shorter....that would be my choice.
 
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What is the mission of the final airplane?

If it's a high altitude cross country machine then the longer -8 wings would be favored. If it's a yank and bank toy, then the short wings will provide the higher roll rate and better ultimate strength.
 
I would consider how the different wings interface with the fuse and what that does to the pilot crew station.

Those are way different spar attachments between the RV-4 and RV-8 wings.
 
Sport wing.

I noticed several differences when I went from the RV-4 to the Harmon Rocket lite.

1. Rides the turbulence better.

2. Lands better. It doesn?t float, and it seems more stable at slow speed.

3. Rolls faster

4. It?s stronger

5.the ailerons don?t get as stiff at high speeds as the stock -4 wing
 
Sport wing.

I agree wit Gt-401. I have owend a Harmon rocket 2 (500hrs) I have built and currently fly a rv8 200hp. I?m not sure how the ride is in a f4 with a 8 wing but my rocket wing felt much better than my 8 wing. I?m basing my opinion on normal cruise through turbulace and gentleman?s aerobatics and roll rate. The Harmon wing is worth the extra work and money in my opinion. I?m looking forward to getting my F1 project in the air and selling the 8. My rocket was 110lbs +over the 8. I wish I never sold my Harmon. I?m building a F1 with a 6 banger but if I was building a f4 I would stick to the Harmon wing.
 
I agree wit Gt-401. I have owend a Harmon rocket 2 (500hrs) I have built and currently fly a rv8 200hp...

I also have both airplanes in my hangar and I agree with you concerning the ride. However, we dont know what the OP's mission is, so its hard to make a recommendation. I'm happy with the short wing because I do a lot of goofing around down low, but when I'm doing my high altitude, straight line for 4 hours type mission, I'd love to have a few more feet of span (and 20 more gallons of capacity). I'm about 50/50 split between airliner style cross country and local yank and bank right now, but if I ever morph into a more cross country centric mission then a longer wing is going to win out.
 
Calling Vince...

I would consider how the different wings interface with the fuse and what that does to the pilot crew station.

Those are way different spar attachments between the RV-4 and RV-8 wings.

I believe Vince will chime in soon, but they are making a spar carry through so that either wing can be used.

Disclaimer: I have yet to finish my project, so someone else who knows more please chime in.
 
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Wings

I've discussed this with Vince. I'm just gathering opinions from those who have possibly flown with both wings and any other considerations. I'm pretty on the fence about what direction to go. Great to have all these options!
 
My top concern would be Vne. If you are going to mount a 4-banger, then the -8 wing would be okay but you still have to be careful. If you are mounting a 6-banger, the -8 wing is out IMHO.
 
Wing

I also have both airplanes in my hangar and I agree with you concerning the ride. However, we dont know what the OP's mission is, so its hard to make a recommendation. I'm happy with the short wing because I do a lot of goofing around down low, but when I'm doing my high altitude, straight line for 4 hours type mission, I'd love to have a few more feet of span (and 20 more gallons of capacity). I'm about 50/50 split between airliner style cross country and local yank and bank right now, but if I ever morph into a more cross country centric mission then a longer wing is going to win out.

So what kind of option includes longer wing and more fuel? I was thinking the 8 QB wing was limited to 42 gal + optional tip tanks ( custom or Hotel whiskey style tip tanks ,no Acro low G with any fuel in tips) I spoke with John Harmon and 60gal is possible with the HR wing..... Maybe a Harmon wing with the 8 span ? My Rv 8 200hp runs out of breathing air above 10k but really good on fuel burn( really good) . I guess if you had a f4 with the HR wing you could convert a 4 to a 6 banger but with the 8 wing your pretty much stuck with the 4? I?m in the same boat as you 50/50 x-country and scaring my self:) I think as long as you respect the VNE of the wing you choose you?ll will be happy with your decision. Great airplanes!!
 
Robert: I try to keep track of the ownership and building activity in the F1 community. Can you share with me the serial number and details of the F1 you are building? You can PM me off-line if you like.


Lee...
 
So what kind of option includes longer wing and more fuel? I was thinking the 8 QB wing was limited to 42 gal + optional tip tanks ( custom or Hotel whiskey style tip tanks ,no Acro low G with any fuel in tips) I spoke with John Harmon and 60gal is possible with the HR wing...

A "long wing" version in the context of this thread would be the 4 banger Rocket with the RV-8 wing. You would essentially have a RV-8, but with the superior aesthetics and ergonomics of the Rocket (IMHO). With a 4 banger 42 gallons is pretty useful, with a six... Not so much.

I will be doing a new set of tanks for my Rocket and have spoken to John quite a bit on the subject. Despite the fact that he's told me it would be easier to build new wings than retrofit, I'm going to give the retrofit a shot. I've had my tanks off and looked around a bit. I have a plan. BTW, the 60 gallon "limit" is merely due to the size of his sheet metal brake. I have method in mind which will allow me to roll a skin at any length so I'll be able to do anything I want WRT tank size.
 
Sorry for not chiming in sooner. I really am out in the shop getting tail kit stuff ready to ship...and not on the computer... if the danged shipping boxes ever get here. I know that sounds kinda lame, but the skins changed, and it made a lot more sense to go with smaller, taller boxes in the hope of making them stronger.

Also sorting hardware, waiting for the last few bits of the kits to get here, a few pieces didn't make it with the other 95% of the kits, etc.

Well, enough update, back to the wing discussion.

As was pointed out in a roundabout way by several above, here's the wing options:

If you're using a 6 cylinder engine, you're limited to a Sport wing, aka a converted RV-4 wing that is shorter span, closer rib spacing, and usually larger fuel tanks. You should use the Team Rocket empennage too.

If you're using a 4 cylinder engine, you can use the Sport wing above, or if you choose, you could use an RV-8 wing. Loyd Remus makes the proper spar carry-thru. The empennage choices include the 4 or 8 tail or the TR tail. Fly the RV-8 wing to RV speeds please.

Answering other questions about which one flies better... ain't gonna touch that opinion-based question. However, I'm building an F4, 210hp Titan IO-370, with a SPORT wing.
 
A "long wing" version in the context of this thread would be the 4 banger Rocket with the RV-8 wing. You would essentially have a RV-8, but with the superior aesthetics and ergonomics of the Rocket (IMHO). With a 4 banger 42 gallons is pretty useful, with a six... Not so much.

I will be doing a new set of tanks for my Rocket and have spoken to John quite a bit on the subject. Despite the fact that he's told me it would be easier to build new wings than retrofit, I'm going to give the retrofit a shot. I've had my tanks off and looked around a bit. I have a plan. BTW, the 60 gallon "limit" is merely due to the size of his sheet metal brake. I have method in mind which will allow me to roll a skin at any length so I'll be able to do anything I want WRT tank size.
Micheal,
Before you go to far with a major rebuild I would consider tip tanks. You can convert your tips to an extra 20 gallons of fuel or 1 to 2 hours endurance at altitude. I have the standard 42 gallons plus an extra 7 per side or an extra hour for me. The nice part is I only put fuel in the tips if I am going cross country so I don't have the extra fuel outboard unless I need it. See some of the previous posts from Fred Stucklen on how to covert your tips to tanks. Far easier then the road your about to go down.
BTW I have been following your posts on electronic ignition and hope to upgrade the rocket soon.
Ryan
 
I appreciate the input Ryan, but I've done a lot of research on this subject and frankly, tip tanks are at the bottom of my list. Such a scheme adds more weight, complexity and is a much higher moment polar than extending the existing design. Yes, installation is going to be a bit of a pain and I already anticipate adding to my already extensive inventory of foul language, but in the end its going to make me feel better.

I do reserve the right to come back to the forum and admit that tip tanks would have been a better choice however.
 
Many RV owners have fabricated their own leading edge tanks that are identical to the stock ones but 50% to as much as 100% longer than the stock ones. Keeps the fuel on the same fore-aft CG point, uses stock plumbing, requires experience fabricating your own skins because you'll probably want it one-piece. Lots more rivets to seal as well...
 
As I think about an F-4 project, I lean towards the RV-8 wing since it has more area due to it's span. This results in a lower wing loading and a lower spanwise loading which results in a smaller turn radius and less energy bleed at high load factors. But I fully admit my mission is probably probably different.
 
Been following along the wing discussion for an F4....no one has mentioned using the stock length RV4 wing with extended fuel tanks.... I assume this is also an option that would give similar Performance to the RV8 wing and simplify the wing to fuse connection.
 
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