Recently, an opinion was rendered on the"Sport Helicopter & Pilot Global Information Exchange"
http://www.usbusiness.com/helicopter/index.htm regarding the the Rinke Aerospace JAG Experimental Helicopter
www.rinke-aerospace.com/ which is supposed to be flying soon...
Donald Hillberg is the designer/builder of the Rotormouse (Rotermouse?)
http://www.pra.org/directory/rotormouse.html
I am curious as to all your thoughts about the JAG, the Rotormouse, and the criticism of the JAG. As regards the JAG criticism, in particular I am curious about the apparent tight clearances between the MR and TR, the shortness of the TR boom, the rounded edges leading to random flow separation and "wallowing and oscillating in hover like an Astar", I've heard this about the Astar, true?
All comments appreciated and I hope its okay to hijack your professional pilots forum for some discussion on the experimentals.
Below find the referenced quote. Also for those that are curious here is the link to all the PRA listings for experimental helicopters:
http://www.pra.org/helicopter1.htm
Thank You,
Hans Conser
DONALD HILLBERG's
(the father of the Rotermouse)
2 cents on the above helicopter.
I have seen the Mini in Drag, a two place, Allison powered A/C and like Cesear, it gets a thumbs down. I talked to the master Head cheese and he attacked and defended his baby ,I will list a number of faults in the "Drag Queen" ,And to cover my but, These are my opinions ,(25 years worth) Now where do I start?
1. Carbon fibre forward cockpit, Once compromised will do nothing to protect the pilots. And
fractured carbon is sharper than sharp ,it will cut you ,stab you, wipe you out.
2. Rounded edges on the tail fan ,Air flow separation / Coannda effect will defect yaw thrust
stability,Increase pilot work load,And as fat as the attachment is to the tail gear box not good
for flow/noise/use of power.(looks like bow thruster on boat)and as short coupled it will be a
foot full. (damn it still looks like a bat part)
3.inproper testing of blades (the web site makes no mention of a real test ,pulling the blade up on
a rig is fun to see but its not cyclic load/sympathetic excitement testing used .He makes mention
that he will not have provisions for pallance.Bad bad
4.Engine to Main gear box attachment no give. I can see transient torque loads damaging the
P.T.O. or cracking the engines main gear case, Any twist,bending,or axial misalignment will reduce the service life of the Allison.
5.No fire wall,and any thing in the baggage compartment will wreak of exhaust fumes,Or worse
the composite body or cowl will light off ,Nothing worse then roasting at 1000 ft,
6.fuel structure said to be molded composite under seat area,I hope its a crash resistant bladder.
7.multi blades to a point is good ,But remember the more blades the more drag in an auto,so like
a 500 or worse the pilot will need a window between his legs to see where hes going. And also the more blades you have the more parts too,and that adds to the cost,and in aerodynamics you will also cost you the unwanted interaction of shed wake vortices rolling under the closely following blade and the increased chance of vortex ring state with so many blades buzzing around above you.
8.Unrealistic performance values,with a steel tube frame,plastic covered body,its not a llama.
9.Nonstandard instrument layout not good for a pilot too much flash,no function,like a Mini all
show no go.
10. smooth belly ,flow stagnation and random separation points will be hard to hover,like an A
star it will wallow and oscillate in ground effect.
12. 222 like nacelles drag drag drag and the rounded edges might induce dutch roll (need
fences)
13.Steel tube frame,Not required for a modern Helicopter.Too heavy for the true designer of
helicopters.( no steel in the 500 or 206 or CH-53 or other high performance Helicopter.)
14.Air flow around engine not uniform might lead to cracking on the hot end or ingestion of
exhaust gases .
15.composite seat area,not a design feature for crash force absourbtion,Once compromised it
will not protest the pilots from injuries,Might even add to the sevarity of injuries sustained.
16.If the hub is machined aluminum and not steel I fear a fretting type failure and blade
separation .(This was just a thought until confirmed by another source.)
17. Untried engine drivetraine combination/surging might be possible ,Ill grant them this one for
now.
18. no room between the rotors and tail boom. I can predict a strike and in flight breakup,Needs
more space.
19.stablizers too big.for desired pitch moment. will nose over in 1st stage of autorotation.adding
to boom strike.
20.Too short coupled needs more length on boom,will not have authority over the torque,
21.My wife (from China) doesn't like it.
So many designers just because they have disposable income think they have the winning
combination and copy a piece of junk and improve on it ,They still have a piece of junk,Its better
to start from scratch and fail then ,succeed with junk that may kill some poor S.O.B. because
good looks can kill.
Don /
[email protected] These are my opinions.
--- DONALD HILLBERG
---
[email protected]