"BENSEN"

Brian Gibbs  large 1/3rd scale gyro

You may click on any photo for a closer view.....

This beautiful  12 pound model has been built by Brian Gibbs,  U.K.....

With the initial tow tests,   he reported that "it got airborne very early , speed 15 mph , with a problem of aggressive pitching up but still stable.   It needed more throw on the gimbel head from 9deg. -to- 12deg. plus 1/2lb.up front with this mod.   A retracking of the rotors also minor adjustments to servo installation also.   We are on the right track,  over all control is very positive with speeds up to 40 mph,  control needs to be a lot softer at the higher speed as over control is aggressive.

The latest up-date we have,  as of August 13, 2000....is that he "had a bit of bad luck friday, 11,  00 ... smashed up a pair of rotors to much flare, also damage to gimbel head, but has been repaired all ready .I have fitted a pair of rotors with a smaller overall dim. these come out at 7 feet the original size being 8 feet , have gone from 1/2 a deg. to 1 deg. positive pitch."

My pre rotator although crude ,  has an electric motor & gearbox from a rechargeable drill ,  the end which held the chuck,  now has a one way bearing and a nylon fork fitted.  This fits over the Teeter block.   .This arraignment is all bolted to the end of a 9 foot alloy boom,   .at the opposite end is a small dry cell 12 volt battery also secured onto the boom with a on/off switch.

This will rotate the rotors aprox. 175  r.p.m.  It works for me,  (will) design an on board later.    Next major change is the motor.   I am replacing the petrol,  23 cc zenoa  for a Moky 210 , 35 cc.   This motor is lighter , so I can remove the weight from the front.

Also have fitted slightly bigger main wheels.   The reason for this I needed more angle on the keel  (and) this will give me a better angle of attack on the rotors  (from 18 to 20 deg.) I`m only using this to achieve faster rotor flight r.p.m.....

Brian`s model features an aproximate 2 meter rotor with Carbon Fiber blades  (with an alloy spar, and an  E360/1  airfoil), and a  6.0  disk loading.  This is an excellent loading for this large/type model.

A rate gyro has been installed for added stabilization for launch,  and hopefully provide added stabilization in flight.  His plans are to test it initially by towing behind a vehicle.    Bryan has built and flown a full sized Bensen and feels that the full sized "towing" procedure will also work well for the model.

Brian lives in the Wocstershire,    England area,  and if you would like to talk to him about this project,   he can be contacted at:   bdgibbs@connectfree.co.uk

rev..8-15-00..jb