News:


Advertise Here

  • September 19, 2021, 10:56:16 PM

Login with username, password and session length

Author Topic: Landing gear wheel position on Rat Racers  (Read 435 times)

Offline Dennis Toth

  • 2020 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 3114
Landing gear wheel position on Rat Racers
« on: August 27, 2021, 10:29:08 AM »
Just a quick questions on the landing gear wheel position relieve to wing leading edge. In stunt we have it straight down for grass or back some for pavement. For Rat style ships going over grass do they have them up under the engine or even ahead of it? Photos would be appreciated.

Best,   DennisT

Offline Bob Heywood

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 933
Re: Landing gear wheel position on Rat Racers
« Reply #1 on: August 27, 2021, 11:43:57 AM »
Dennis,

The correct reference is the wheel contact point on the ground relative to the aircraft CG. The default position for conventional gear is 15 deg ahead of the CG.

For grass moving that point forward is helpful. I don't have any data to say how far forward.

The attached scan is from the 1949 NAA rules for 190 cubic inch class racing airplanes (aka Goodyear racers)
"Clockwise Forever..."

Offline john e. holliday

  • 21 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 21821
Re: Landing gear wheel position on Rat Racers
« Reply #2 on: August 27, 2021, 11:51:50 AM »
In the old days the wheels were usually just behind the prop.  Some were even ahead of the prop.   D>K
John E. "DOC" Holliday
10421 West 56th Terrace
Shawnee, KANSAS  66203
AMA 23530  Have fun as I have and I am still breaking a record.

Online Ken Culbertson

  • 21 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 3610
Re: Landing gear wheel position on Rat Racers
« Reply #3 on: August 27, 2021, 11:54:32 AM »
In the old days the wheels were usually just behind the prop.  Some were even ahead of the prop.   D>K
Ours were just behind the prop but the guy I flew for was so good at pitting that the wheels rarely touched the ground!

Ken
AMA 15382
If it is not broke, don't fix it.
USAF 1968-1974 TAC

Offline Bob Heywood

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 933
Re: Landing gear wheel position on Rat Racers
« Reply #4 on: August 27, 2021, 12:08:40 PM »
For pavement, a shallower angle may be used in order to facilitate pulling the plane into the pit.
"Clockwise Forever..."

Offline bob whitney

  • Moderator
  • Trade Count: (0)
  • Admiral
  • *****
  • Posts: 2041
Re: Landing gear wheel position on Rat Racers
« Reply #5 on: August 27, 2021, 01:15:24 PM »
Bob is correct  15 deg works for just about everything on pavement .on my stunters i move the wheels about 1 in forward for grass

back in the day we didnt know about 15 deg by moving the wheels up by the motor and extending the  tail skid to almost level we could get a pretty good hot (for the day) landing
rad racer

Offline Dennis Toth

  • 2020 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 3114
Re: Landing gear wheel position on Rat Racers
« Reply #6 on: August 28, 2021, 06:42:32 AM »
For flying of grass with these types of ships one of the concerns is having the prop and lines survive the landing. Yes I know APC props can take a lot of banging around but there are better prop choices that are less sturdy (wood, some thin glass). Our field is a grass soccer field with nicely mowed surface but still not like pavement. For Stunt 1 3/4" wheels get off and down nicely. I'm wondering with this style ship (rat, FOX35) does the more forward wheel position give a more survivable landing without the ship flipping end over end?

Best,   DennisT

Offline Bob Heywood

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 933
Re: Landing gear wheel position on Rat Racers
« Reply #7 on: August 28, 2021, 08:21:23 AM »
At the Chicago - Glenview NATS there was a very large, nicely cut grass lawn behind the work hangar. After hours there were C/L planes of every description being flown. I flew my Royal Rodent off the grass with the same set-up as pavement. We used K&B Racing Wheels in those days. No problems.

As a side note, the highlight of the evening was killer combat. 10 or more planes in the air at the same time. When one landed or crashed someone else went up. All evening 'till it got dark.

Just build the thing and fly it...
"Clockwise Forever..."

Offline Trostle

  • 21 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 3036
Re: Landing gear wheel position on Rat Racers
« Reply #8 on: August 31, 2021, 10:22:40 AM »
Dennis,

The correct reference is the wheel contact point on the ground relative to the aircraft CG. The default position for conventional gear is 15 deg ahead of the CG.

The attached scan is from the 1949 NAA rules for 190 cubic inch class racing airplanes (aka Goodyear racers)

Bob,

The drawing you showed is excellent.  Bill Netzeband showed similar drawings in several of his columns over the years and also in his 5-month long series on how to design and fly stunt ships in the mid 1950's.  That same 15o angle from the CG applies pretty much to all full size, conventional gear aircraft.  One thing to note is the 15o puts the point of contact of the wheels on the ground, not through the axles of the wheels.  Not that it makes that much difference for our models, but for relatively larger diameter wheels, it starts to make a difference.  Also what needs to be considered is the measurement is from the aircraft CG including consideration of its vertical CG.

Keith



Offline Dennis Toth

  • 2020 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 3114
Re: Landing gear wheel position on Rat Racers
« Reply #9 on: September 01, 2021, 06:38:09 AM »
To Keith's point, for the small rat size ships that have gear for an 8" diameter prop you don't have much airplane weight that can settle the ship down once the wheels hit the ground. In stunt there is considerable airplane so the overturning moment is a little more controllable plus you have large wing area aft of the CG and significant control surface to stabilize the ship. With the rats hitting grass, should the same 15 deg angle hold or should it be a bit more forward?

Best,   DennisT

Offline Bob Heywood

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 933
Re: Landing gear wheel position on Rat Racers
« Reply #10 on: September 01, 2021, 05:36:27 PM »
Here is the sort of plane we raced in the 1960's. The Royal Rodent set-up was very similar. Forget the science. This worked anywhere. Go fly your model.
"Clockwise Forever..."

Offline C.T. Schaefer

  • Trade Count: (0)
  • Captain
  • *****
  • Posts: 601
Re: Landing gear wheel position on Rat Racers
« Reply #11 on: September 02, 2021, 05:00:22 AM »
T.O.R.  =   Tri-O-Rama field at Rich's Hobbytown in N.J.  Lots of us were greatly influenced by that place!

Online Ken Culbertson

  • 21 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 3610
Re: Landing gear wheel position on Rat Racers
« Reply #12 on: September 02, 2021, 07:05:51 AM »
Here is the sort of plane we raced in the 1960's. The Royal Rodent set-up was very similar. Forget the science. This worked anywhere. Go fly your model.
Yup

Ken
AMA 15382
If it is not broke, don't fix it.
USAF 1968-1974 TAC


Advertise Here
Tags:
 


Advertise Here