LE Nose Gear

[MikeD]

I have fitted the electric nose gear assembly by Jack Wilhelmson and am now finishing off the attachment to the strut.

At the moment I haven't floxed the parts to the strut, they are fitted as per the drawings (all measurements are correct) and I have read the following from the installation instructions:

2. The down micro switch is not critical except to make sure the aircraft has a
positive ground angle of 1 ½ to 2 degrees UP angle as measure on the longerons
for minimum ground run on takeoff and to keep the NG15A shaft from having a
forward angle.

My measurements are at best 0.5 DOWN, that means the front wheel would have to be a least 3 inches off the ground before the longerons were at 1 ½ degrees.

The wheel is already touching the rear part of the wheel well so I can't gain anything by moving the wheel further down the shaft.
I've fitted the engine but not the prop or wings so there is already a lot of weight on the main gear.

Questions:
1. With wings and fuel etc. how much deflection is there in the main gear, would it be enough to get the longerons to 1 ½ to 2 degrees UP angle.

2. Are there any documents showing the  measurements from the centre line of the prop to the ground (I've spent hours searching)

MikeD (U.K.)

[srothert]

Mike,
If you are using the 500X5 wheels/tires, you may have to trim the main landing gear to get the proper angle on the longerons.  If you haven't mounted the axles yet, it is relatively easy.  Might have to take off 1 inch or more.  I cut 2 inches off of my strut and it was a little too much.

Steve Rothert
Long-Ez N49SR
Albuquerque, NM.

[MikeD]

Steve,

That's a very useful bit of information, Yes it has the 500x5 fitted so this is probably what is causing the issue.  Once again, many thanks.

MikeD (U.K.)

[Super-EZE]

Mike I have the same situation with my plane after just mounting the lift. Hold off until the near end of the build and make your adjustments then.

[srothert]

Keith,
That is a great idea also.  When I made the measurements to cut the main gear strut, the plane was upside down and that was a mistake.  If you decide to cut the main gear, make sure that the engine is mounted, put some weight in the front seat (equivalent to an average pilot weight) and some weight in the rear seat area (equivalent to some gas and/or rear seat passenger).  If you have the room in your workshop, pull the plane forward so the main gear begins to assume its normal taxing attitude.  Then make your necessary measurements.

Steve Rothert
Long-Ez N49SR
Albuquerque, NM

[EZRider]

How critical is his issue?

[dkreidel]

Not very critical. I moved the MG forward 1" from plans on 8EZ  and 1" aft from plans on 26EZ, and irrespective of angle of attack on the ground the TO ground roll and rotation speeds are similar.

dk

[go ez]

Isn't he asking about the effective angle of attack of the canard when on the ground roll?

Granted,  moving the MG fwd or aft will slightly decrease or increase the load the canard has to lift when the wheels are on the ground but if the canard AoA is negative on the ground roll, it will take more speed and/or elevator deflection to lift a given weight on the canard to lift the nose to get the canard flying. At some point, too much take off speed, take off roll or elevator deflection will be reached.

Obvious I know but the canard must fly ie rise before the main wing can do any lifting (ie there is no prop wash over a tail plane to help raise the main wing AoA to get it to fly as you can do in a conventional tractor aircraft)

Rutan increased the rigging AoA of the LEz canard by 1 degree compared to the VariEze so he thought it relevant.

Engine and wings weight does make a big difference to the longeron angle to the ground

Steve (UK)

[dkreidel]

You are 100% correct,  but I've removed the spring from the NG shock strut and tested TO distance/speed with the canard at a negative AOA and it didn't make much difference - 100 to 150' delta at mid-weights. 
The only variable on a given airframe/engine combination that really impacts TO distance and Vr is water on the (GU) canard, high density altitude, and high gross weights.

Dick

[go ez]

Thanks for that Dick - that is really good reference quantitative data that is useful to know.
Regards
Steve

[dorr]

The original spring on the Long EZ can be augmented by using a Cozy IV spring - which might also bring up the nose a little - but wait to weight is on the plane and check longeron "level" is best advice.

Beagle