Conversion from short to long legs

[RV-4]

Hello everyone

I sometimes think about converting my RV-4 short legs to the long ones and I'm wondering how hard of a conversation and how expensive it might be..

Is there anyone who has done the job who could share info?

Thanks

Bruno
rv4@videotron.ca

[bizjet]

I am curious why you would want to make that conversion.

Regards,

Bill

[designerX]

Originally Posted by bizjet

I am curious why you would want to make that conversion.

I'm guessing prop clearance and/or easier 3-point landing when loaded with aft cg.

[mtnflyer]

I made the change years ago,,It will make it much easier for you to three point.

[mickdi68]

I was just talking to my wife about putting the longer gear legs on our 4 when this post just came up. It would be good to have that bit extra prop clearance . Was just looking today at someones 4 with the longer legs and while mine is apart at the moment would be a good time to change them . Any comment's for or against ?.

[131RB]

Bruno,
I did a conversion several years ago on a freinds airplane. He had purchased it, not built it. He had a hard landing and bent the gear up bad enough that it needed to be replaced. You really need to take everything into consideration before making this mod. It may go very smooth and it may be just the oposite. In his case he had the old style cowl with a 4" prop extension. When we put on the new motor mount and legs we came up with several problems. The first problem was that the baffling and engine no longer fit right in the cowl. No amount of work seemed to right the situation. To make a long story short the baffling was shot and needed replaced anyway. Without completely reworking the cowl it wouldnt fit right. Ended up with a new cowl and of course that ended up needing a 2" extension, we had to rebuild the filtered airbox, let us not forget that this also leads to needing a different spinner, not to mention bolts, hardware ect. The gear angle is different and the brackets for the wheel fairings and brakes are different. New brake lines (no big deal here)
I am not trying to discourage you from doing it just making you aware of some of the things that may come up.
I have flown both the short and long leg versions and saw no great advantage of the long gear legs. I will say that when one sits next to the other that the long legs look a little nicer. I never had a prop strike with my short legs in over 1100hrs of flying so I dont see prop clearnace as an issue. If your are flying with an 0360 with a longer prop it may be.
I would have to say if your tires wear evenly and everything works the way it should I personally would leave it alone. Good luck either way
Ryan

[smokyray]

Bruno,

I have performed the "switch" twice. To do it right requires a new engine mount as well since they are match drilled by Harmon Lange. Big job. I flew my RV4 for 10 years with short legs out of my 1100' rough turf strip in AL. Also have many hours in friends Long-legged RV4's.

Adding to Ryan's, here's my pro's and con's list from the cheap seats.

LL Advantages: Slightly shorter STOL takeoff. (higher AOA)
Slightly better 3 point STOL landings (less TW first)
Better prop clearance (fewer rock dings, if you venture off road alot)
Better looking "curb appeal"(in my humble opinion)

LL Disadvantages: Poorer forward visibility during taxi
Slightly more drag
Lots of work and $$$ to convert (wallet stress)
Longer moment arm on engine mount/firewall stresses.

My advice:"If it ain't broke, don't fix it"

V/R
Smokey

PS: On inspections I see many more buckled firewalls and cracked engine mounts on Long Gear airplanes, mainly from poor pilotage. (The Short gear have less moment arm and less shimmy). I guess Bob Axsom would even tell you the Long Legs have more drag, which they should.

[Russ McCutcheon]

Originally Posted by smokyray

I have performed the "switch" twice. To do it right requires a new engine mount as well since they are match drilled by Harmon Lange.

Not to pick nits but you absolutely have to have a new engine mount, regardless of drilling, the long leg mount has the gear sockets at a different angle so that the wheels remain in the correct place relative to the C of G and the long legs are larger in diameter and will not fit in the old mount.

[RV-4]

Hi Guys

Thanks a lot for all the feedbacks...greatly appreciated

There are no special reasons for wanting the long gears legs except the sex appeals that is all..

With a 3 bladded Catto, prop clearance is not a factor and I mostly do main gears landing first rather than 3 pointers anyway ..

I was curious at the work and expenses involved in the process but with all your good advises, I will stick with what I've got..It has been working fine for the last 12 years ..

Like Smokey says :"If it ain't broke, don't fix it"

Thanks again

Bruno
rv4@videotron.ca

[Clouddancer]

Bruno

We replaced the on our RV-4 the shorter gear by the longer new one.
Background: We bought the 4 from a previous builder that had it not completely finished. We wanted to have a new O-360 instead of the old O-320 that came with the project. Additionally the landing gear legs were not finished (needed heat treatment). -> Yes, he did even the landing gear legs on his own!

We found some additional points that you might consider:
You will need a new engine mount as mentioned by Russ and Smokey.
The center bolt holes that attach the engine mount to the firewall will not line up with the existing holes, because of the changles angle. We also had to fabricate some washers because the engine mount did not contact the firewall. And of course, the washers needed to be slighly conical as well, because firewall and engine mount were not parallel.


On our airplane the lower corner bolt holes did not align completely as well. We solved that by fabricating some special bushings from stainless. A hole story of its own...


Just some additional points, if you want to make the trade off the cooler look against the work to be done.