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Design => Engineering board => Topic started by: Don Hutchinson AMA5402 on April 25, 2016, 07:48:06 PM
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Help: old age is catching up with me! What is the magic angle for the landing gear on a tail dragger? 15 or 17 degrees ahead of the CG? I know it is a number many of ya'll use but I'm drawing a blank today.
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Actually, I think "15 or 17" is probably about right -- put it further forward if you fly off of grass, and back if you fly off of pavement.
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Down at the moto cross track ( just kidding ) I was astounded eyerybodies was Fwd. of the L.E. ( axle line )
15 is what ive seen mentioned .
Oriental ( no taper ) is under the L.E.
Bowlin Greens , if well maintained , and tarmac , are less likely to trip it up than rugby fields . Though they maintained the rugby fields fairly well at Whangaporoa ,
the park in winter was a marsh , so they ouldnt get the tractor on to mow in the rains , so the long bits or passpalum could catch your lines , though thats not the wheels .
Nice Puddles for the float plane , but the lines'd catch a lump before it got off , every time . Spent a morning being chased by the aeroplane , surprisingly without wrecking it ,
before I gave up , as it hadn t stopped drizzling .
:-\ R%%%% H^^
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Just Put this Elsewhere , but it does illustrate why some people might compare it to a M-X Track , in comparison to a Bowling Green . and explane the Fwd. Wheel Posn . ;)
(http://controlline.org.uk/phpBB2/files/petepracticeday_151.jpg)
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Hi Don,
This goes back to the articles and columns by Bill Netzeband. For a conventional gear, the place to position the main gear works out to be 15o forward of the CG. This works for any configuration - delta, canard, flying wing, saucer, conventional, swept wing or whatever.
Essentially, this works for full scale aircraft as well.
Now, if you have really smooth surface, you can move the main gear rearward a couple of percentage points and be able to get some really nice smooth landings. But do not move the gear so far back that the nose might tip over. (With the fuselage level to the ground, the axles would be on a line drawn 15o from the CG. If you place the point of contact of the wheels with the ground at 15o, then the axles will be more than 15o to the CG and the model becomes more prone to bounced landings.)
And as has been suggested earlier in this thread, if you are always flying off of grass, then move the gear forward.
(For a tricycle gear, the main gear can be between 10o and 15o behind the CG. Here, just do not place it so far forward of that range that the airplane might just rest on the tail.
Keith
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as Keith said 15 deg for pavement about 1 in forward for grass, dont go any farther back than 15 deg
i have wheel pants on both and the pavement gear will tip at the last second on grass ,.1 in forward and it will grease right in, same on take off
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Thanks Keith, that is the answer I was looking for, the number used on full scale as well as stunt ships. Turns out the warbird profile I am drawing up right now measures very close to your figure. Now I will wait and see if anybody asks "What airplane is it?"
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Thanks Keith, that is the answer I was looking for, the number used on full scale as well as stunt ships. Turns out the warbird profile I am drawing up right now measures very close to your figure. Now I will wait and see if anybody asks "What airplane is it?"
What airplane is it? ;D
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If you are old enough to remember this "I'm a no gonna say", that is my response until this one is finished. Maybe that way I can stir up enough curiosity move more than 4 or 5 copies!
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Not the P-36, however if I had been thinking I would have made provisions on the drawing of the P-40 so one could build a 36, as well as the 40-C or 40-Q from the drawings! Actually, anyone could add the radial cowl and have one.
Don