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Date: June 15th
Rotorway gas turbine powered conversion
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Mid 1993 I had the pleasure of meeting Dave & Walter Domanski, They were interested in the RotorMouse and wondered if the same type of power plant that was in the EH 1-01 could fit in their Exec 90 Rotorway.

We sat down at Bobs Café and over burgers and drinks we sketched on the napkins an idea of how to fit a gear box and engine into the airframe.

The Solar / International Harvester T-62 T32 from an M1a1 generator set from Military surplus was used, a turbine of 150 hp, no time life limits, 145 lbs.

The modifications were few and just a set of tabs for the engine (Mount) and another set for the gearbox (torque relief) and a shaft driven tail rotor.

We put the engine on top of the frame behind the mast for maintenance and C/G issues. We found that the ballast amount could be reduced.

A Speedway Motors catalog was used for parts and a Winters Racing rearend used on Midget race cars as a main gear box, tabs,

nothing like a catalog full of bearings and other pieces. a rotational molded plastic fuel tank was made capacity of 45 gallons (3 hours worth of fuel)

In 1994 a "prototype" was finally assembled on Walters helicopter - The clutches chosen were problematic as the diaphragm would lose its temper and the spring forces lost.

A new industrial clutch from a Honda wood chipper was put in and the engagement was too brisk causing compressor stall and rough starting, The fix was spring washers on the disk to slow down engagement - a balance between easy start and not slipping with high torque loads was accomplished.

Dave and Walter spent their free time refining the final design for marketing and along the way they were balancing the main rotors and tweaking the Rotor RPM gage.

Dave was leaning in with the instrument panel open adjusting the gage when the engine started surging - Walter rolled the helicopter on the pad out side their shop.

Walt saw Dave disappear out the door as the blades hit the deck and Dave saw the engine explode as the turbine section was slammed between the airframe and fully loaded helicopter. Both thought either one was injured or dead. Dave and the spinning blades of death or Walts flaming explosion.

The source of the surge may of been caused by radio interference from the nearby March Air Force base, Causing the surge.Modifications with the governor system was employed and B.J. Schramm notified of the issues as they used the same power section & electronic governor, But Eagle R&D suffered a fatal accident losing B.J.

I figured the heavier rotor system reduced the effects during surges and the lighter rotor system on the Helicycle had no dampening causing engine runaway.

The helicopter was promptly repaired and flights resumed until Walter made a new roll up door for the shop using the rotor blades, only damage was a bent rotor mast and a sheared bolt in the tail rotor drive shaft. (never saw a mast bent 30 degrees). Walter and I spent a few hours in a Brantley B2B to get the rust out of his flying...

In weeks the helicopter was flying regularly with Dave at the controls and extra ballast (Dave was a big guy and he liked to add weight laterally to level out the ride)

Helicopter # 3 was started at Corona Air Port with a taller mast (Removes the need for ballast) and a manual override on the governor system , But the owner took it back to San Diego before scheduled flight tests.

Many owners expressed interest in the conversion, and KISS Aviation was started for the conversion kit sales and support of the Jet Exec owners.

SN 98 Jet Exec attached. [blue]

SN # 3  [red]

The Original Jet Exec #1 [white with everything open]

 

 



-- Edited by hillberg on Monday 15th of June 2020 09:27:31 PM

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Date: June 15th
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hillberg wrote:

Mid 1993 I had the pleasure of meeting Dave & Walter Domanski, They were interested in the RotorMouse and wondered if the same type of power plant that was in the EH 1-01 could fit in their Exec 90 Rotorway.


 At that point was it the Honeywell 36-55-C or the Solar T-62?



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The Mouse had the AirResearch 36-55-c (later Honeywell) I paid $500 for it (A lucky find) hard to find ...
and the Solar T62 T32 was chosen for the Jet Exec because...
1- it would fit with 150 hp
2- It was more plentiful then the Honeywell.
3- you could buy an M1A1 gen set surplus for $1500 (today $6,000)
I sold them the first sets for the project. (The conversion kit was sold without the engine ) A list of surplus agents were provided.

But the best thing was Solar was made into a conditional power plant and only a few had the turbine wheels with a cycle life limit.
The affected SN turbines were removed from inventory in 1997.
If it's not leaking, Shaking, or not maintaining rated horse power limits you can continue to run with an inspection every 300 hours in situ.

BJ Schramm would buy simi trailer loads for the sets for rework in the Helicycle.


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Date: June 16th
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Awesome, thanks for sharing your story on this design! Some adventures and sketchy situations, but I suppose it's to be expected in experimenting with new ideas, and a successful thing came of all the hard work (over a hundred kits sold is a good number). Do you know what happened to #3 after it was taken back? Did it ever fly?

Also, what became of the original prototype? Is it still around?

Now for my contribution to the topic; I found this article during a research spree and I think it should be included since it dives pretty deep into the technical aspects of the design for those interested:

http://www.redbackaviation.com/rotorway-jetexec-turbine-powered-kit-helicopter/

And here's some pics from the article:



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Videos via the same source:



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Date: June 16th
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SN#3 is with its owner near San Diego He was a farmer and was scared during the 1st run up - Never knew what happened after he left.
Dave still has the original and I've lost touch after Walter passed on. Don't know what their doing at Western Metal Spinning...

Kit # 98 was another strange tale
Steven B. was building a standard Rotorway kit at Camarillo Air Port and was partnered with our local FAA rep. Jerry. (FAA only lets co-owners play)
I helped a little on the kit doing rotor smoothing and it's first hover and the owner then practiced adding time and experience as Jerry tagged along.

One day Jerry went solo taking the helicopter to pester Steve as he was playing a round of golf in the local club.
As Jerry burned off fuel the c/g changed so the cyclic changed position when he approached to land.
All would of been fine if he remembered to remove the collective for solo flight, But as he slowed to a final hover the collective pinned with his leg stopped any lateral cyclic for a hover to landing.

Jerry not thinking things out slammed the collective down and spread the skids, bent the blades and wrinkled the tail cone.
Jerry made good for the damages and Steve then went for the turbine conversion, as it was cheaper then buying the parts from Rotorway.
When talking to Jerry he was wondering why the helicopter wasn't climbing at 100 mph down the runway I told him best climb was at 50 odd mph with a little aft cyclic, His eyes looked like a light just shown him a forgotten fact,,, It wasn't a fixed winger.

After Steve finished the project he regularly flew from Camarillo to Paso Robles, A few months later at the Sheriffs Air Unit office Jerry was doing his duties as the FAA primary checking on our helicopters, just another day at the office.
He was taking a break before his next appointment when Steve called, he was stuck in the fog on top of some mountain in Santa Barbra and wanted to get advise on high altitude operations ie: taking off after it cleared up.

Later Steve called again asking if the Air Unit could air lift his helicopter off the mountain as he tobogganed through the bushes and trees on a down wind down slope take off.....Jerrys advice was a little off.

Last I saw Steve was rebuilding it again. that was in 2010...

Joe's Turbine exec has an Allison 250 c 18 in it and sits in the high desert of Inyokern Ca,
Stu Fields The old Editor from Flying Magazine owns it now.



-- Edited by hillberg on Tuesday 16th of June 2020 02:15:01 PM

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Date: June 17th
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hillberg wrote:

The Mouse had the AirResearch 36-55-c (later Honeywell) I paid $500 for it (A lucky find) hard to find ...
and the Solar T62 T32 was chosen for the Jet Exec because...
1- it would fit with 150 hp
2- It was more plentiful then the Honeywell.
3- you could buy an M1A1 gen set surplus for $1500 (today $6,000)
I sold them the first sets for the project. (The conversion kit was sold without the engine ) A list of surplus agents were provided.

But the best thing was Solar was made into a conditional power plant and only a few had the turbine wheels with a cycle life limit.
The affected SN turbines were removed from inventory in 1997.
If it's not leaking, Shaking, or not maintaining rated horse power limits you can continue to run with an inspection every 300 hours in situ.

BJ Schramm would buy simi trailer loads for the sets for rework in the Helicycle.


 So it was an... Abrams engine? I'm confused. I thoght Chrysler and Lycoming/Honeywell were given the contracts for the gas turbine powerplant?



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He's talking about a ground power generator set, it was a coincidence in military designations. The T62T-32A was commonly used for several types of GPUs for the Navy and Air Force, and still is to an extent. The EMU-30 is another example.



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Date: June 17th
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AIR FORCE / ARMY Generator set M1A1 palletized -
Powered by a Solar/International Harvester T-62 T32 (T- 62 was the designator of Manufacture- Solar) see list below. . .

ANA bulletin 306 from the Pratt Whitney pocket engineering guide 1973
T 30 Westinghouse
T 31 GE
T 33 Flader
T 32 P&WA
T 34 P&WA
T 35 Wright
T 36 Chrysler
T 37 GE
T 38 Allison
T 39 Allison
T 40 Allison
T 41 GE
T 42 DeLava
T 43 Wright
T 44 Allison
T 45 P&WA
T 46 Fairchild
T 47 Wright
T 48 P&WA
T 49 Wright
T 50 Boeing
T 51 Continental
T 52 P&WA
T 53 Lycoming
T 54 Allison
T 55 Lycoming
T 56 Allison
T 57 P&WA
T 58 GE
T 59 Boeing
T 60 Boeing
T 61 Allison
T 62 Solar
T 63 Allison
T 64 GE
T 65 Continental
T 66 Solar
T 67 Continental
T 68 Rolls Royce
T 69 Continental
T 70 Westinghouse
T 71 Allison
T 72 Continental
T 73 P&WA
T 74 UACL
T 76 Garret
T 78 Allison
T 80 Allison
Changed to MIL STD 879 in 1967 for growth using same numbering system.

The Pratt Whitney pocket book is full of great information
Engine design specs
Rocket motor specs
Rotor blade forces
Chemical design
and math /decimal to fraction tables
drill conversion
power formulas

Lots of neat stuff





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