Landing Gear Conversion

I have a (kit that was purchased in the late 80's) flying RV4 with Short Gear legs, 0-360 injected Lycoming with a wood 68" prop. Even with the 68" prop, I have only about 5" of tip to ground clearance in level static attitude. Hence I only make 3 point landings.
If you have or had a 'short legged' RV4, is this what you have for tip to ground clearance?
Has anyone converted the short legs to the longer legs on most RV4s? How many hours did it take, what is involved and do you consider it worth the investment? ljb

New engine mount

Yea one friend went thru this, and again second friend decided not to make the change, despite needing an new engine mount. If you replace the gear legs with the new longer ones, you must change engine mounts , but you probably already knew that. That gets expensive. I have not priced the engine mount and legs but it will be well over a grand.

Bottom line get the check book out if you want to do this. A new set, engine mount, legs, fairings, brake lines and other possible changes is going to cost.

It is not hard to do but you are replacing a large section of the plane, and it will take some serious time. Here are some things you may not have thought of.

You will no doubt want to also replace the mount bracket's on the back of the firewall with the newer design for two reasons. The old ones could and do crack (not all). Two, chances are the mount holes will not be perfectly aligned with the new engine mount, but who knows you might luck out. They are not expensive but they are a PAIN to get out.

Also the cowl may not fit the same with the new engine mount. It will be close, but there are tolerances. I don't recall a cowl issue withmy two freinds but THEY both opted to change their engine mount firewall brackets. O ne needed them (cracks) or the other found the mount did not fit as well as he liked on the existing holes and decided to take the oportunity to upgrade the brackets.

In the mid late 90's Van's Aircraft transitioned between the short and the current longer gear. The two fellow RV-4'ers I mentioned changed their engine mounts. One opted to go with the new mount and longer gear legs that just came out, and the other did not make the change and bought the old style engine mount so he could retained his old gear legs.

The one guy needed a new engine mount because he was going from conical to dynafocal and needed to replace the whole engine mount. With the new engine mount he decided he wanted the new longer gear legs and of course new fairings, brake lines and wheel fairings....... It was expensive but he liked the stance better.


The other guy decided to buy replace his damaged engine mount with another original design engine mount. Van was selling the old design engine mounts at a discount compared to the new ones just coming out. Also he did not want to replace his gear legs and all the other stuff that goes with it. Van was going thru a transition and still had some old ones in stock. This guy with the short gear legs was swinging a Hartzell (72") and recalled he had adequate clearance; granted adequate and great are two differnet things.

I sold my RV-4 a few years ago and it had the older mount and legs and it sat a little higher than other RV-4's (with original gear legs)? Some RV-4's look real squat where the spinner center is lower to the ground? I don't know if that's in-part from how it's built or if some had "set" from hard landings? Gear legs can and do bend. I am not saying that's the case, but I could never figure out the appearance of some RV-4's being shorter than others, and this was before the new longer gears come out way back in the 80's and early 90's. I don't know if Van had an original shorter legs?

In both of the cases above they changed their firewall brackets.They both had cracks, but both where hard core aerobatic, dog-fight, formation guy's.

If I where you I would not bother, unless there are other reasons like you are taking the engine mount off to replace engine mount brackets. The plane will not fly better. You will spend a small fortune and it will be a big pain in the ......... RV-4's land just fine tail low and wheel landings are overrated. 5" clearance is 5" clearance. If I can help let me know. George

Short Vs. Long Gear

I'll second what George said. I considered this change on my short geared RV-4 also, but ultimately decided not to do it because of the large number of other things that have to be redone when making the conversion. My O-360 powered -4 started life with a 72" Sensenich. Off hand, sitting here at home I don't recall what the static ground clearance was but the measurement from ground to spinner tip was the same as another -4 we had in the hanger at the time. So, I think my plane is representative of the breed. As part of my worrying about this issue, I did tip the airplane up until the prop was just tangent to the ground. The nose down attitude in this test was very low...and would certainly get your attention if you tried to wheel-on in this attitude. (Granted it didn't include pilot weight, landing dynamics...blah..blah...blah...)
Here is a picture where I had the plane in a static attitude with the 72" Sensenich, and it looks like about 5 inches of ground clearance, but I can't tell from the old grainy photo.
[img=http://img527.imageshack.us/img527/3850/image1082iw.th.jpg]
Having said all that, I did switch to a 68" diameter Whirlwind 151 constant speed prop about 150 hours ago. There were many factors in that decision, and without getting into any of the debates that switching to that brand and type of prop could spawn, I will say that improving my ground clearance was a factor.
Another thing to consider is the over the nose visibility. With the short gear, I have excellent straight-ahead visibility...this would be degraded somewhat with the longer gear.
The short vs. long gear thing is certainly a personal decision, but as George pointed out, it's going to be a lot of time and money to switch to a long gear, and for me...not worth it. Most of the time I try to land in a 3-point attitude or very tail low so the short gear is not a factor.
Though I hate to recall it, perhaps this story will make you feel better. When I first completed the -4, I proudly flew my new plane to Stephenville for lunch with some of the BCs. I elected to do a wheel landing (with the 72" Sensenich), but botched it badly by misjudging how high I was and flying into the ground way too hard. The initial contact and subsequent bounces were high and hard, but the prop never contacted the ground. Now, let us never speak of that event again
Good luck!

bad landing!

I have had people say they have never landed there airplane badly, badly might be relative but any one who tells you that is probably bending the truth. I have about 6? clearance and have landed poorly also with no problems.

I am quite sure on request you can still buy a brand new mount of the old style for your -4.

I have a -4 with the long legs. I would really like to be able to see over the nose during taxi and landing. I do have quite a bit of available space between my headset and the canopy, but I also have a two level fusion of the cervical vertabrae...with the kind of turbulence we experience in the Rockies, I think I'll keep the clearance. I prefer wheel landings for the over the nose vis, but on any decently wide runway, three pointers are no big deal. Narrow, short runways are another story. I've never been comfortable when the entire runway disappears in the flare. One other thing I've noticed, is that with strong gusty winds, landing in the three point attitude and catching a gust can raise a wing dramatically. Exciting. I prefer to wheel it on and get it slowed down a bit before increasing the angle of attack by lowering the tail.
Your mileage may vary.