question

[matt]

does anyone have a solution to this problem, on a racer design little more than three feet wide with a quadruple landing gear arrangement (the two main gear mounted about two feet out on the wing) the first two gear swing up to the rear of the wing and the rear two swing up to the front and into the fuse behind the wings.

the question is this, how would you either get the front or rear set of gear to turn for ground taxiing. please be specific enough for it to be drawn or better yet do your best to draw the planform.

matt

[Old Ramp Rat]

Re: question

does anyone have a solution to this problem, on a racer design little more than three feet wide with a quadruple landing gear arrangement (the two main gear mounted about two feet out on the wing) the first two gear swing up to the rear of the wing and the rear two swing up to the front and into the fuse behind the wings.

the question is this, how would you either get the front or rear set of gear to turn for ground taxiing. please be specific enough for it to be drawn or better yet do your best to draw the planform.

matt

If your not worried about tire wear of everyday use,
DIFFERENTIAL BREAKING..?

[matt]

Re: question

with a car type arrangement would differential breaking work? i can see both sides of that argument and it just seems to me as if it wouldn't

[Old Ramp Rat]

Re: question

with a car type arrangement would differential breaking work? i can see both sides of that argument and it just seems to me as if it wouldn't

Probably need a few more specifics...but it works in some tanks, and ATV's, with throttle....forward, brake-back "L-type" handles, as sole controls. *Entertaining driving sequence of little ATV's, in the (space) movie, "Silent Running" (I think), with Bruce Dern....

If you get into hydrolics, there was a concept car, a while back, with a single stick, center mounted controll(er), nothing on the floor.....stop/go/left/right, (great for driver changes...)

...as a sidebar, I'd be concerned about about putting to much weight, (ie: wheels & brake assemblies), too far outboard...."dumbell effect"....but there are those, wiser then I, that could advise you, on that...

[Gary Osif]

Re: question

If the front pair are allowed to 'free-caster' and use diff braking on the rear mains.....maybe. Or, make the fronts controllable and linked to rudder pedals. I would need a drawing/blueprint to view to be sure.

Gary

[matt]

Re: question

this help?

[Old Ramp Rat]

Re: question

[QUOTE=Gary Osif]If the front pair are allowed to 'free-caster' and use diff braking on the rear mains.....maybe. Or, make the fronts controllable and linked to rudder pedals. I would need a drawing/blueprint to view to be sure.

Gary[/QUOTE

The Grumman AA-1/TR... series are pretty common if you want to look at the front wheel swiveling arrangement: some interesting arrangements on some amphibious float systems: Cessna's pretty unique with there retracts, ie.210...but wheels are weight, think you're planning on one too many. (You can have a single, non symetric nose wheel), THINK Rutan's done that..

Old freind use to say, "throw something up in the air...... if it hits the ground, it's too heavy for a race plane".

[First time Juke]

Re: question

Matt,

Where do ya need so many gears for ? Did I miss something here ?

rgds,

Juke

[Gary Osif]

Re: question

Very snazzy looking bird! It looks like the stall speed may be pretty high with that design.....

It would appear you want two struts in front due to engine clearance, am I right? Have you thought about just offsetting one(i.e. A-10 Warthog)?

Have you ruled out trying it as a taildragger?

Am I creating more questions than answers? Sorry.

GO

[hattend]

Re: question

Or if not a taildragger, how about a bicycle arrangement ala B-52 or Harrier? Little outrigger wheels in the wing with streamlined pods and a rear set of gear that are steerable.

[matt]

Re: question

alright let me answer all these questions in one foul swoop.

1. the weight question, total weight of the air plane should be no more than 3000 lbs loaded, as it's about the size of a lancair with no passengers or cargo. so another gear (about .01% more weight) really doesn't mean a whole lot weight wise.

2. the major reason for a four gear arrangement is visibility on the ground, granted there won't be much, but if it were a taildragger it would sit like tsunami.

3. the high stall speed is a very valid question and unfortunately that's a question that will have to be answered when a wind tunnel can be made or...would anyone be willing to make a 1/4 or 1/5 scale model of the plane?

4. finally a bicycle arrangement wouldn't be stable enough, it works on large planes like the b-52, but the u-2 has a tendency to ground loop, and with this plane (which will most likely need to land faster than most prop planes) it will probably have that same tendency.

lol, gary i welcome questions man, ask away.

[jarrodeu]

Re: question

would it be that easy to ground loop with the wingtip wheel stabalizer things like on the Harrier?

http://www.aoqz76.dsl.pipex.com/Web%20Page%20Components/Wallpaper/Planes/Harrier.jpg

Jarrod

[matt]

Re: question

well see, my understanding of it is that there are certain parameters at which the bicycle type (with training wheels ) will work and the harrier follows them, i want to keep the wings as clean as possible and outriggers just would not allow for that. the extra landing gear adds weight that's true, but large fairings under the wings create drag. more drag for what is essentially the same number of landing gears.

also, all of the fuel will be stored in the wings so i would have to have the outriggers pretty far out on the wing, beyond those given parameters.

it's a great idea, don't get me wrong, but for this particular plane i don't think it would work

[Gary Osif]

Re: question

Your estimated stall speed can be found by calculating the wing loading.

I beleive it's the planes total weight divided by total wing area(or vice-versa). So, if you can estimate the final weight and since you have a final dimension of the wing, you can find the square ft. of area in the wing. Being a swept wing might be a bit tougher and I'm betting the real brains out there can describe and calculate it better than me!

The front gear is gonna be substantial to get the prop clearance needed!

I was trying to envision a possibility for you that would be similar to a taildragger, with a taller tailwheel strut for vision. Ground looping was mostly the concern and also the aforementioned hefty front mains for prop clearance.

So, I'm still raising more questions than answers!

GO

[Old Ramp Rat]

Re: question

1. the weight question,doesn't mean a whole lot weight wise.
*Weight IS always an issue @ 4-6 "G's"

2.a taildragger would sit like tsunami.
*Not neccessarily a problem, depending on the "stick"

4.bicycle arrangement wouldn't be stable enough
*BEEN THERE/DONE-THAT with biicycle gear, would't recomend it.

*single off-set nose wheel (castering ok), sounds like the best bet.
Looks like you'll need room for the exhaust, any way

*outriggers/dual linkages.......K.I.S. KEEP IT SIMPLE The more parts you have, the more parts you have, the more that can fail