Grove landing gear

[sdemeyer]

I'm thinking of switching my standard gear to Grove gear, before I get arrested for DUI
.
I hear that the Grove gear makes a much improved difference in ground handling. Looking for feedback from someone who has actually done this before I fork out the $$. Does it really make that much of a difference?

[DesertFox4]

Yes!!!



I was just going to reply with the above one word answer but you deserve more. I had a model 3 years ago that the factory tube gear made "exciting" to land and take off with. Now you really don't spend lots of time taking off in a model 3 with a 912 on it but the little time it took to raise the tail and pull the stick it was anybody's guess which way it would point. Very seldom did it settle on straight down the runway. Landings induce a pucker factor high on the scale. Inject a cross wind and all bets were off. All due to the gear being cambered out and toed in. Any weight shift at all induced directional instability. Now some would say that makes you a better pilot to be so aware on landings but I'd just as soon skip the blood pressure spikes at my age.
Bottom line is my Kitfox's will have Grove gear either in tail or nose configuration. Very robust , wider stance , better handling, gun drilled brake lines, great company support and worth every penny charged. I enjoyed landings after the Grove gear installation. Best of luck Scott.

[sdemeyer]

No, not too heavy. 652 empty. Yes, I checked the toe. It's toed in about 1.5 degrees. I would think that should be adequate. I don't seem to have an issue going straight in the J-5 Cub nor a Citabria so I'm blaming my meandering around the runway, on the KF landing gear

[DesertFox4]

Scott with the 912 you'll notice very little if any difference in performance with the Grove gear. I didn't on my model 3 except the ground handling was vastly improved. Added weight is always a concern on any Kitfox but the added safety to every flight exceeds any penalty you pay for the net gain.
The Grove gear for the model 3 & 4 Kitfox weighs 24.3 lbs. Of course you'll subtract the weight of the original gear from the Grove gear to get your net increase.

Another gear you might check out, if you haven't already, is the new gear Kitfox Aircraft has for sale.
More of a bush type gear. Not sure what they weigh but they are on the Kitfox Aircraft website in the parts catalog on page 35 part number 13050.000 for $1450.00.

[sdemeyer]

Thanks for the info Steve. I'm headed to Arlington this afternoon so I will talk to the Mcbeans and see what they have available. I compared the LG on my KF with another and it appears mine is not the same. My gear has much beefier tubes is a little taller and the axels have a different setup. Looks like the original builder may have made custom gear.

Scott

[HighWing]

I wouldl like to offer a little correction to the Grove gear weight and a suggestion regarding toe in. First, the weight of the Grove gear listed on their website is the gear leg only. I talked to a rep and asked for total weight including brackets and fasteners. After a delay, which I presume was to put everything on a scale, I was told the weight was just short of 31 lbs. I seriously doubt you will find any aircraft accessory or part that is advertized with the actual installed weight anywhere in the literature.

Regarding the toe in at 1.5 degrees and being just about adequate. Toe in is seriously destabilizing - any toe in. Parallel or slightly toed out is much better. This can be achieved at little or no cost. I still have my copy of the factory newsletter describing the method for correction - bending the gear. I also flew with both sets of gear with little difference. I changed because of gear failures rather than handling. I did tweek the gear before first flight though. I ended up with a 700 lb. Model IV. My buddy flew with a IV weighing 600 lbs. Side by side, we were close, but I never won the cigar. I guess it depends somewhat on where you want to go.

A serious suggestion, before forking out the big bucks, try tweeking the gear. You may find that that vacation to (insert fantasy destination) suddenly has become more possible now.

Lowell

[jtpitkin06]

There have been a few posts about toe-in and toe-out on aircraft without really explaining the geometry of the spring type landing gear design. This does not apply to oleo strut, trailing link or bogie truck type gears.


With no weight on the wheels, a spring type gear has positive camber by design. This means the top of the tire centerline is tilted outward. Negative camber means the top of the tire is tilted inward.

As the aircraft enters a flare the pitch increases. With a pitch increase, the positive camber factors into two components, part positive camber and part toe-in. When the weight of the aircraft settles on the gear, the gear spreads. The spreading changes the positive camber into negative camber. This transition is more pronounced at higher weights. As long as the aircraft attitude is nose up with weight on wheels, the now negative camber factors into two components… part negative camber and part toe-out.

This transition from positive camber to negative camber, and toe-in to toe-out occurs on both conventional gear and tricycle gear.

If the aircraft has conventional gear, and negative camber with weight on main wheels and tailwheel, it will always have toe-out in the three point attitude.

However, if the aircraft is tricycle, the nose lowers after touchdown. This causes the toe-out effect of negative camber to transition back to near neutral toe-in while maintaining negative camber. ( There is a slight decrease in negative camber when some of the weight shifts to the nose gear.)

For tricycle gear aircraft, toe-in is stabilizing. As the aircraft turns, it leans against the outside tire. Because the CG is ahead of the tire the toe-in counteracts the turn much like a vertical stabilizer. Most tricycle gear aircraft are set up with slight toe-in with weight on all three gear.

For conventional gear aircraft, toe-in is unstable. As the aircraft turns it leans against the outside tire which is pointed into the turn. Because the CG is behind the landing gear the aircraft turns sharper and over-steers

Toe-out on a conventional gear is stabilizing. As the aircraft turns it leans against the outside tire which is pointing away from the turn. The tire angle decreases the turning tendency and directional stability is easily maintained by the pilot. . Most conventional gear aircraft are set up with slight negative camber with weight on wheels which results in a small toe-out component.

For an example of conventional gear toe-out stability one can look at aircraft equipped with “crosswind” landing gear. If too much pressure was put on the outside tire, the entire wheel simply casters to an extreme toe-out condition and removes any turning tendency.


If your aircraft is a bit squirrelly on landing, you might check the camber and toe angles with the aircraft loaded to the normal operating weight. If the gear is too stiff or bungees are too tight the gear may not be settling into the preferred negative camber position.


In summary, tricycle gear --- neutral or slight toe-in is best. Convention gear --- neutral to slightly toe-out is best.

I hope this clarifies the differences between conventional and tricycle landing gears and how they react with camber, toe-in and toe-out.

JP

[Luvn737s]

I used to be active on a Skybolt and related biplane forum and the subject of retrofitting a spring-steel gear like a Grove onto a design that originally used tube/bungee suspension would come up. Some said that the spring-steel gear concentrated the load too much and could lead to fuselage tube cracking. Is the KF design susceptible to this?