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matt
10-04-2004, 11:06 PM
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
10-05-2004, 09:26 AM
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
10-05-2004, 01:24 PM
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
10-05-2004, 07:42 PM
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
10-05-2004, 07:59 PM
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
10-05-2004, 11:39 PM
this help?

Old Ramp Rat
10-06-2004, 01:22 AM
[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
10-06-2004, 05:15 AM
Matt,

Where do ya need so many gears for ? Did I miss something here ? :1zhelp:

rgds,

Juke

Gary Osif
10-06-2004, 10:41 AM
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. :D

GO

hattend
10-06-2004, 12:01 PM
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
10-06-2004, 12:33 PM
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
10-06-2004, 12:42 PM
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
10-06-2004, 01:01 PM
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
10-06-2004, 01:32 PM
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! :dunno:

GO

Old Ramp Rat
10-06-2004, 02:11 PM
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

jarrodeu
10-06-2004, 03:36 PM
Wouldn't wing thickness affect the stall speed also?
Jarrod

matt
10-06-2004, 03:59 PM
hmmm, 3000 lbs / 104.4 sq. ft = 28.7 lbs/ft.

this is how much clearance the props will have

like i said before there wouldn't be much vision but the pilot would better be able to see around the nose with this arrangement than a tail dragger.

lol, like i said gary, ask away man, these are problems that need solving, still though taxiing it will be hard to figure out.

Gary Osif
10-06-2004, 05:48 PM
What engine/prop do you propose? The current Merlins are just under 11.5ft. diameter on the prop. So, you need 6ft(minimum)from c/l of spinner for that engine.

I'm thinking at 3,000lbs total, you are looking at a smaller powerplant.

For weight and simplicity, I would consider the taildragger. A good pilot will have no problem weaving during taxi to see. With the swept wing, placement of the mains might still be tough.

GO

matt
10-06-2004, 07:36 PM
lol, good post old ramp rat (who are ya anyway if you don't mind my asking)

under 6 g's that 3,000lbs would shoot up to 18,000, meaning that the weight of that extra landing gear would be around 300 lbs. granted that's a lot of weight but still if i got rid of it the plane would weigh 17,700lbs, not a whole lot of weight loss, and the way the plane is designed is to not have to fly at 4-6g's on the course for the entire race.

about how the plane sits, you're right, it does depend on the pilot but any pilot will tell you that they like being able to see as much as possible.

i really designed this plane around the engine and exhaust system, if you look at the area in front of the wing it indicates engine size and turbo and exhaust arrangement. the layout is outdated though, the engine i intended to use never came to fruition. so i'm looking at a ford 502 which will provide more than enough power.

Apteryx
10-07-2004, 12:42 AM
lol, good post old ramp rat (who are ya anyway if you don't mind my asking)

Wayne finally convinced me to go legit, changing user name to Apteryx. I'm by NO means an engineer, and math just hurts my head, but I've got 20+ years crewing and a few more helping out home-builders, so I draw from my experience & common sense, and I'm NOT a mechanic, but I play one @ Reno. Also of note, I haven't built anything of my own, (yet), wicked sinus infection wiped out my inner-ear, NO FLY without GOOD drugs....

I'm a good friend of test pilot, Dave Morss, and have had the privalage to go with him on several first inspection/flights. I try to stay out of his way, and observe, but on one occasion, I gave what I THOUGHT was a sub-audible "snerk" while inspecting a new wonder. The "published" designer waisted no time in telling me, HE was a GENIUS, and I was witnessing, the future of aviation....Evenually they managed to get the sucker in the air, once in 20 years. Sometimes you can be TOO smart.

Anyway, back to the subject, that 300lb gear now requires uplocks, pivots, etc...that will hold the extra weight.....

SOLUTION: no gear, Teflon skids on the belly and just dead-stick it in;
(Germans thought it was a good idea)...OK taxing IS a B*tch.....

P.S.- cool looking design.
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THE SKY'S THE LIMIT, well actually, it isn't anymore............

matt
10-07-2004, 10:54 AM
lol, well, come prs lets get introduced.

ya, dave's a good guy, lots of fun. i refuse to say this design is the "future of aviation" bad luck always seem to come when an owner makes that remark.

pivots and uplocks wouldn't cost me that much more weight.

so the question remains how would one steer?

jarrodeu
10-07-2004, 11:23 AM
I don't know that much about airplanes but could you independently brake the wheels. Like brake the right wheel to make it go right. :dunno:
Jarrod

matt
10-07-2004, 12:49 PM
that's what differential braking is jarrod, part of the problem with a car type gear arrangement is that for differential braking it's too stable. it does not want to turn and causes extra wear on the gear.

Apteryx
10-07-2004, 11:35 PM
[QUOTE=matt]
so the question remains how would one steer?

Look forward to meetimg you, going to TRY to hit PRS this year, at LEAST, (although flying days are over, (for a while), I hope, still have a lot of friends, up there. Missed TWO Reno's in a row now, then there was 2001......I FEEL the NEED.....................

Dave should be the one to pipe in here, he's flown a lot of UNIQUE, stuff.....but I've got about 100 hours messing around in Grumman AA-1 & TR-2's (free castering, differential brakes), with no problems, there's a few things out there with the nose gear off-center, I don't think IT would care. Still perfer a taildragger, but trike (off-center), doesn't worry me. Weight items mentioned not THAT big a deal, but especially in a racer, the fewer parts, the better. MUCH more fun SEEING them fly, rather then trying to make them fly, but looks like you've been there....

If your thinking of venturing in Unlimiteds, don't follow Sea Furies, the wake will knock the snot out of you, starts break'n stuff too....
They are the "speed-bumps" for the "little" guys.

(think about the skid idea, if you can swing Budweiser as a sponser, the Clysdales can tow the plane in, after they've unloaded the beer.... you'd be quite popular).
.................................................. ...................Paul

matt
10-08-2004, 11:11 AM
sweet, it'll be good to meet you.

i'm looking a little more closely at a trike config, i'm updating the design and in a few days hope to put it up.

lol, it is an unlimited but i don't intend to be *behind* any sea furies.

but not too popular with the clean up crew, hehehe

Apteryx
10-08-2004, 11:18 AM
[QUOTE=matt]

but not too popular with the clean up crew.
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With all the bull sh*t floating around, don't think anyone would notice...

matt
10-08-2004, 11:31 AM
i'm getting a whiff of truth from that :eek:

Apteryx
10-23-2004, 02:56 PM
i really designed this plane around the engine and exhaust system, if you look at the area in front of the wing it indicates engine size and turbo and exhaust arrangement. the layout is outdated though, the engine i intended to use never came to fruition. so i'm looking at a ford 502 which will provide more than enough power.
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There are several Mazda rotary powered ships flying, and now, one of the racing shops, is building a 3-rotar 900hp Wankle engine. If you can mate the drive systems, that would move your 3000lbs, right along.... :D
(with less frontal area), I've got a picture of the engine, if I can figure out how to send it................................................ .Paul

matt
10-23-2004, 08:12 PM
i've gotten some interesting news on race engines recently and aircraft design. when i get more info about thte engines i'll put it up

Apteryx
10-23-2004, 08:45 PM
i've gotten some interesting news on race engines recently and aircraft design. when i get more info about the engines i'll put it up
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Take a good look as well, at the photo's of Aberle's prop, in the bi plane class.
Always thought of props as sort of a black-art, (sure proved his on to something, though). REALLY would hate to prop the sucker....

If your changing your design, from a "crew" standpoint, rear engines make the airplane, SO much easier to clean.......... :D .......Paul