Aircraft Update!

Time to update the current inventory of planes and kits.

As of today the Mitchell Wing T-10 kit has been sold.  Stephen and Traci (spelling?) of Pueblo, Colorado made the long trek to Aumsville, Oregon to pick up their new project.  Steve has an engineering background and is very enthusiastic about getting the kit completed. I look forward to his future build updates.

The Cumulus Glider kit was sold a month or so back to Jim from Tennessee.  Jim took 5 separate flights to arrive at the Eugene airport, spent one night at a hotel, rented a truck, loaded the kit up and made the odyssey back to Tennessee.  I think the whole trip took him about 10-12 days.  He is also very excited about his new project.

The Sky Cycle Trike was sold locally last year toward the end of the flying season to Steve from Roseburg.  Steve had flown just about every type of aircraft except a weight shift trike, so this was a definitely a new adventure for him.

Finally, within the last few weeks I sold most of my remaining props, engines, ultralight aircraft parts to Mark from Southern Oregon.

All I have left is the Mini Max 1550 V-Max.....and I finally have enough room in the hangar to put on the wings!

Mitchell Wing T-10 Two Place Motor Glider Kit for Sale! SOLD!

The T-10 motor glider kit is still for sale at the reduced price of $7500!  Kit is as new and complete, less engine, prop and instruments.  The aluminum over foam factory built wing sections are still covered with the original protective plastic.

This kit may be the only one in existence, allowing you to build a legal Mitchell Wing T-10 two place motor glider in either the "Experimental Amateur Built" category or "Motor Glider" category.

Flying Again!

After a ton of work the Sky Cycle/Manta trike combo is finally flying.  I finished up the carb jetting, pitched the prop to pull 6100 rpms at WOT, and adjusted the hang position to cruise at 45 mph.

I have to say that she came out really great; looks great, and flies great.  The weather has been a little iffy, but I have been stealing some short flights here and there and look forward to the return of high pressure.

I have a few more things to tweak here and there, but overall this airplane is pretty much done.

What's next?

Birth of the Sky Cycle!

Since my last post I have made great strides of progress on the Sky Cycle.  I mounted the engine, ran the fuel lines, hooked up the electrical and mounted the instruments.

I decided that the 64" Warp Drive prop was too large, even on a 2 blade hub, so I cut it down to 60" and am running it as a 3 blade.  It is smooth and powerful!

When I first ran up the new 440 engine it ran fine, but was pretty boggy in all rpm ranges.  The carb was obviously set up too rich, so I put in a bigger jet needle and took the main jet down a couple of steps.  I am most likely also going to lean out the pilot jet as well.

I am really happy how well everything has come out and I think that this trike is going to be a perfect fit for the 17m Manta. 

All that is currently left is to take the wing off of the old 340 Kawasaki trike and mount it on the Sky Cycle for its maiden flight!

Found a Prop!

I have been searching for a prop for the Sky Cycle for some time.  The custom trike with the 340 Kawasaki engine simply did not produce enough thrust with the 58" 2 blade Powerfin prop and 2.5:1 reduction drive.

To increase thrust on the Sky Cycle I had the chassis built as light as possible, while adding a larger h.p. engine and a bigger reduction drive.  The final step was to get a larger prop.

As far as props go, there are a lot of options out there, IVOs, Ultra-Props, Powerfins, Warp Drives, etc.  One needs to decide on not only the brand, but the composition, diameter, and number of blades.  The final decision needs to be factored by the h.p. of the engine, ratio of the reduction drive and clearance between the prop, aircraft and ground. 

I decided to try to find a good used prop as new props with hubs and blades are quite expensive, while good used props can generally be found for 50% or less of new.  After a lot of searching I found a nice 64" 3 blade Warp Drive.  It is currently being shipped to me from Michigan and I should have it in about a week.

Three blades at a 64" diameter is pretty much the largest possible prop that the Kawasaki 440 can throw, given the 2.67:1 reduction drive and ground/aircraft clearance that I currently have.  It is quite possible that the prop may actually be a bit too large for my application.  I will not know until I pitch the blades and run it up.  If I am unable to get the 6200-6600 desired rpm's at wide open throttle I will have to make some adjustments.  I will either need to cut the blades down a bit in diameter, or purchase another hub so that I can run a 2 blade prop.

I am looking forward to testing it out.

Behold the Sky Cycle Trike!

After a bunch of test flying on my custom trike I came to the conclusion that the 340 air cooled engine was not going to cut it in terms of my expectations.  It simply doesn't produce enough thrust for the 17m Manta wing.  This fact, along with other previously mentioned issues prompted me to look for a more powerful engine.

After searching diligently on Barnstormers and Craigslist I found a low hour re-build Kawasaki 440 down in Texas.  The 440 will produce at least 10 more h.p. and is also fan cooled, which will eliminate the cooling issues I had with the 340.  This particular 440 also has a larger reduction drive, 2.67:1, meaning I can throw a larger prop as well.

After purchasing the engine I started thinking again.  Even if I put the 440 on the custom trike, the overall setup is still going to be heavier than I really want for the 17m Manta Wing.  For this wing I need a very light and powerful trike chassis.

So I started shopping for a new chassis as well.  I was hoping to find something used in excellent condition as this would be the most cost effective way to go.  Nothing ever really came up so I started looking at new units.  I finally settled on the Sky Cycle trike.  The Sky Cycle is quite well known and a lot of them have been built.  The builder Michael Theeke at Fly Hard Trikes is very easy to work with and promptly responds to all questions via e-mail or phone.  Mike does quality work and I would definitely recommend him to anyone looking to purchase a new trike.

The photos show the basic unit as it was shipped to me.  I received the chassis a little over a week ago.  So far I have it uncrated and put together with the engine mounted and exhaust and carb installed.  I still need to hook up the electrical, run the fuel lines and add the instrument pod.  By the time I am done it is going to be a very sweet little unit!

20 Test Flights Later

In the last month I have been doing quite a bit of test flying of the trike.  There were, and are a couple of issues that still needed to be sorted out.

First of all was the hang position.  After the first flight I went back to the manufacturer to re-confirm the stock hang position for the Manta 17m.  According to Mark Gibson at GibboGear, the hang collars are originally set so that the back of the hang block (plastic cubes) measure 28 1/4" from the back of the keel.

After setting the block at this position I flew the trike again.  Throughout the flight I continually needed to push out quite a bit to climb, and after leveling off I found the control bar at cruise to be nearly touching my chest.  I concluded pretty quickly that this stock position was too far forward for my trike.  I slowly moved the hang position back at about a 1/4" at a time.  The farthest back I flew was at a measurement of 27" from the keel.  I finally settled on 27 3/8" which seemed to produce the best cruise speed and bar position.  This is 7/8" aft of the stock position.

The next issue is one of power.  With full power I am able to climb at a rate of about 500 feet/minute.  This is definitely not stellar in my opinion but acceptable.  The real issue is at cruise speed.  To maintain level flight I need to pull higher rpm's than I feel I should have to.  Full throttle is at 6600 rpm's and to cruise I need to pull 6000 or more.  I should be able to throttle back a bit more.

This basically boils down to a problem of thrust.  My Kawasaki 340 runs strong, so after doing a bit of research I concluded the following.  The Manta 17m is a low aspect wing and requires quite a bit of energy to keep it airborne.  I am simply not turning a big enough prop to produce the thrust that I need for this wing.  I have a 58" 2 blade prop with a 2.5:1 reduction drive.  The best setup would probably be a 66" prop with a 2.8:1 reduction.

The last issue is of cylinder head temperature.  The Kawasaki 340 is air cooled and the rear cylinder generally runs 25 degrees or more hotter than the front cylinder.  Furthermore, the whole engine runs a bit hot.  The engine sits behind my head which blocks air flow to the whole engine, with the rear cylinder being affected the most as it is behind the front cylinder.  Although I am able to keep the CHT's in check by running the engine rich, to maximize horse power I want to try to get the whole system to run cooler at a leaner jetting.

Back to the drawing board.