Landing gear location

[Jim Roselle]

Hey all,

I am currently building a mongoose for club racing. I am to the point of installing the landing gear. It will be a single wheel setup. How far ahead of the CG should the wheel be?

Thank you,
Jim

[Paul Smith]

I think they ground-handle best with the gear so far back it almost falls over on the nose.  Remember fuel weight.  I'd say even with the LE is a good start.

[bill bischoff]

The commonly quoted answer is the point of wheel contact should be 15 degrees ahead of the CG for nice "TR style" wheel landings. If you're using a wire gear, put the wheel at the leading edge and tweak it as required. If you're using an easily removable aluminum gear, same thing. Slot the mounting holes or make another gear if necessary. If the gear is permanent, get out the protractor so it's right the first time! If you're the pilot, you know how important it is to get the wheel in the right place. If you're a pit man, believe the pilot when he says the bouncy landings aren't his fault.

[Motorman]

How many props do you want to buy? If you put it too far back it will nose over if: the pilot pulls it sideways, you have a tail wind that catches the underside of up elev, you hit a pebble, you hit a crack, dried castor in the wheel, wheel hub too short for the wheel width. your pit man pushes it. My wheels are near the front edge of the tank.

MM

[Jim Roselle]

How many props do you want to buy? If you put it too far back it will nose over if: the pilot pulls it sideways, you have a tail wind that catches the underside of up elev, you hit a pebble, you hit a crack, dried castor in the wheel, wheel hub too short for the wheel width. your pit man pushes it. My wheels are near the front edge of the tank.

MM

This approach makes sense as I will be flying off grass.

Jim

[Jim Thomerson]

The 15 degree figure is exactly right for flying off a hard surface.  For grass make the 15 degree measurement and then move the wheel forward one inch. 

[PaulGibeault]

Hi Jim,

My own (Fox Powered) Mongoose's L.G. is located 5/8ths of an inch fwd of the wing L.E. I use a 2" rubber wheel. Seems to work quite fine. If you use music wire instead of sheet aluminum, you can quickly adjust it as necessary... Good luck, it will be FUN, as the Mongoose is a tried & tested, proven excellent racer!

Cheers, Paul 



I am currently building a mongoose for club racing. I am to the point of installing the landing gear. It will be a single wheel setup. How far ahead of the CG should the wheel be?
Thank you,
Jim

[Motorman]

The Mongoose I built had 1-1/4" wing, I use it for sport stunt. My racers have a 1" wing. Is there a Mongoose 2 kit?


MM

[Jim Roselle]

Thanks guys, this what I came up with:


Where to mount a tank on that short nose is a whole other issue:

[Motorman]

From the NCLRA web site:

Fuel System: 2oz tank Max. No pressure, vents may be directed forward. Fuel must enter tank through 1/8 diameter tubing. There are no restrictions on venturis or needle valves other than venturis must not be of the swing-weight type. If an RC carburetor is fitted, it must be wired to maintain a fixed opening. No inboard fuel tanks.

MM

[BillLee]

He did say "club racing" and not NCLRA-or-AMA-anything. OTOH, if he wants to fly where those rules apply, then he will have to address the tank and its placement.

[Motorman]

I'd take that spring off the needle and meter it with the knurled barrel. I'd run it with and 8-6 plastic and you're going to get about 90 laps if that's a 2 oz tank. OS makes a nice acorn nut that might save your catch hand. I like the horn on the air vent.

MM

[Jim Roselle]

It's for Central Arizona Control Line Clubs' " vintage racing". About 25 vintage models to choose from, Fox or McCoy 35 stunt or any unmodified .25, no speed or racing specials, club supplied top flite 9x6 and club supplied 10/20 fuel. Heats are 2 up, 50 laps with one mandatory pit stop. Final is three up with two mandatory pits. We're just getting it started, hopefully we can support a four race series alternating between Phoenix and Tucson.

Jim

[Jim Roselle]

I'd take that spring off the needle and meter it with the knurled barrel. I'd run it with and 8-6 plastic and you're going to get about 90 laps if that's a 2 oz tank. OS makes a nice acorn nut that might save your catch hand. I like the horn on the air vent.

MM

Motorman,
 Will do on both counts. The horn is a Tee Dee .049 venturi.