| There
is no mention anywhere in the literature regarding this aircraft being built for a
gasoline engine. So if you decide to do this, you may be on your own regarding warranty.
No big deal, I put gasoline engines in all of my airplanes regardless if it's made for gas
or not. However I do have a list of things that need to be beefed up for gasoline engine
use.
1) The firewall gets
fiberglass re-enforced
2) All CA hinges are replaced with
real hinges
3)
All control rods are beefed up or replaced
4) replace the glow fuel tank with a
high-quality gasoline specific tank
It really dosen't take much effort to make ANY aircraft gas engine worthy, but you do
need to plan your build to include the necessary changes. Always
make Safety your FIRST priority.
ABOUT the Engine:
An Evolution 26GT is (in essence), a glow engine
factory converted to a gasoline engine. It's a 1.55 cubic inch (25.5cc) or commonly known
as a 1.60 engine. Because it is a conversion, this engine will fit
anywhere a larger glow engine would go. This makes the 26 GT a well suited engine for
smaller scale models like the 1/5th scale Rearwin Speedster. It's also a very light weight
engine as compared to other 26cc gas engines. As far as power goes, the 26 GT is as
powerful as a Zenoah G26. My Evolution engine is actually a little more powerful than a
Zenoah G26. My engine benchmarked a 16x8 APC prop at 9300 RPM. That's 400 RPM more than a
Zenoah 26 and its 20 OUNCES lighter! 20 ounces in an aircraft such as the 1/5th scale
Rearwin Speedster is substancial. In other words... this is one incredably potent
and light weight engine for a small gasser.
ABOUT the ARF:
I did a complete parts count, and inspected it for damage. No
parts missing, and nothing broken. the control surfaces were pre-hung using CA hinges but
not glued in. I DO NOT use CA hinges for gassers. I have had very bad experiences with
them. For this bird I used Great Planes 1/4 scale hinges. These are strong pinned hinges
and can withstand the virbration generated by gas engines. As the photo depicts,
installing these hinges is nothing more than pushing them into the existing CA slots.
A closeup of the GP Hinge
Some people like to glue their hinges in place, and this will work fine.
However, I prefer to anchor them with #2x3/8 button-head screws.
Here is the horizontal stab hinged and ready for elevator halves. This is
a very clean and easy install. I am very pleased with the quality of this ARF. It is well
designed and well fitted. The hardware is of good quality and it has semi-phenumatic tires
instead of those crappy foam tires often found in most ARF's. I do think the tires are a
bit small though. I switched to 4" diameter and they fit perfectly in the wheel
pants.
As you can see, the Evolution 26 is a perfect fit! I did make a change in
the engine mount. by using an aluminum one instead of the plastic mount provided in the
kit This is just my personal preference for gas engines. The nylon/plastic
mount is OK for most all engine applications. I am using a full-length Tuned
Pipe on my 26 GT and it fits nicely. The purpose of the pipe is, I get an
extra 800 RPM out of my engine. The available Pitts Style muffler will work FINE as well,
however I prefer power over looks. Again, its just another personal preference. A gas
engine historically vibrates more than a glow engine. This engine is an exception since
its origin is glow. On the other hand, I am putting a 1.60 engine into a .90
sized aircraft so special attention is manditory. The firewall MUST be
re-enforced to support the extra weight & power.
Here is a close-up of the engine installation.
The stand-off box needs to be fiberglassed and/or screws installed at the
intersection of the box. I would also suggest additional tri-stock wherever possible.
Other than that, it's ready to go. You'll notice the engine is inverted... Again, my
personal preference. With the engine being inverted the cowling will need minimum cutting
to fit, and it will have a much cleaner look. So far, this aircraft has been my EASIEST
gasoline engine conversion to date. The supplied fuel tank is an 18.5 ounce glow fuel
"stopper style". You can use this tank if you change the stopper to a gasoline
compatable stopper. I replaced the factory tank with a B&B Specialties tank which is
specifically for gasoline. It's a 16 ounce, which is really too big for my gasser. It will
easily fly 50 minutes in a single fill-up.
Unlike J-3 Cubs and Monocoupes the Rearwin Speedster has a semmetrical
wing profile similar to a Taylorcraft or a Citabria. Also, the fuselage is fairly narrow
and tall which will make air penetration a little less difficult. The tall fuselage will
make for excellent knife-edging. The large vertical fin has a slight draw-back for some
aerobatics, but that's easy to overcome. The coupling ratio is fairly long so you can
expect the aircraft to track nicely with minimal yaw.
In order to counter balance the extra weight of the engine, I added a second
elevator servo and moved them both to the rear of the fuselage. (You can see the left
one in the photo above.) this balanced the aircraft perfectly AND it gives the aircraft precise
elevator control. The aircraft balanced perfectly in the neutral position with the
servos moved to the rear.
I kept the original rudder servo location but changed the wood
dowel to a fiberglass arrow shaft with .093" rods. This is much more ridged.
You may install a PULL-PULL system if you like, as the proper cutouts are already in the
fuselage. For servos, I used a pair of Hitech HS 625 Metal Gear for
the ELEVATOR, and HS 5625 MG Digital for the
ailerons & rudder. The throttle servo is an HS525MG.
My radio is a SPEKTRUM DX-7, operating at 2.4Ghz. The receiver is 6.0
volt and the ignition is 4.8 volt, and both are 2700 Mah NiMh. You won't need high
capacity batteries if you use standard servos.
Because I will have two batteries (ignition & receiver) I had to look
for a unique place to put them. I wanted them accessable, AND beneficial for balancing the
aircraft if necessary. I came up with installing them in the bellypan. This turned out to
be fantastic! I did secure the bellypan with covering AND the supplied screws to insure it
stays on.
Kangke got a little carried away with cut-outs for weight reduction. You
will want to cover these off cut-outs to keep the fuselage from getting pressurized, AND
to keep fuel vapor out! I just covered these cut-outs with Ultrakote.
The Rearwin Speedster is
done. Its weight came in at 11 pounds, 12 ounces, having a wing-loading of 28 ounces per
foot. She's going to fly like a charm!
MISSES:
The Manual leaves a lot to be desired for novice builders. It does not cover all the
component installation.
Way too many cut-outs in the wood, especially in the firewall & stand-off box
great tires, but a little too small
control pushrods are low-budget (wood)
HITS:
great looking aircraft, nice colors, nice lines
fiberglass cowling & wheelpants and already painted
Good quality hardware
semi-phenumatic tires, they are a little small though
Easy to build, all parts fit properly and covering matched up.
Excellent FIT & FINISH
All I'm lacking now is a maiden flight!
After one final check of the controls, I taxiied out and lined up into the
wind. At about 1/3rd throttle she rolled out smooth & straight, not needing any rudder
correction at all. I pulled back on the elevator and she climbed straight up as high as I
wanted to go. I leveled off, and she locked on to course headed north. I needed NO AILERON
TRIM, NO ELEVATOR TRIM, NO RUDDER TRIM! Amazing! After about 7 or 8 laps around the field
I had to add left aileron trim. I knew Something was up... I landed only to find the left
strut came lose at the wing. After a little creative re-work it was ready again. The next
flight was flawless. It knife-edges perfect... It flat-spins perfect in both upright &
inverted... It's capable of a rudder snap on demand, but you have to want it to snap, as
it takes a sudden full rudder. It's also capable of an elevator snap, but you have to
force it by increasing your elevator travel as far as it will go. It's a very graceful
snap, and easy to recover from! Next time out, I will "try" some 3D type
maneuvers just for fun. I'm not expecting it to perform well, but it may be surprize me...
Speedwise, well all I can say is... The 26 GT pulls it with great authority! Actual speed
is approximatley 70.98 MPH or 354 MPH scale speed.
Landing is a total no-brainer, idle her down and float her in... This is a very gentile aircraft to fly even on windy, gusty days.
However, throw the controls to maximum... and be ready! This
aircraft is eager to comply with your wildest commands!
The Evolution 26 GT & Rearwin Speedster is a perfect
match and there wasn't a single speck of oil to be found on the aircraft.
** LONG LIVE GASSERS**
FINAL NOTES:
Kangke did a nice job with this aircraft. It makes an excellent gasser with the
correct engine and it flies magnificent. If someone was looking for a first gasser and an
airplane easy to fly, this would make an excellent choice. Inspite the poorly written
manual, the Rearwin Speedster is a quick & easy to assemble aircraft.
UPDATE Oct 28, 2007
I have about 25 flights on the Speedster now. I can say with a very high degree of
confidence, that this is one superb flying aircraft! I have had a couple of
dead-sticks (all my fault) and the Speedster landed perfectly each time. I don't own
another airplane that will land this nice under dead-stick duress. It just floats home...
UPDATE July 12, 2008
My Rearwin Speedster now has well over 250 flights and she's still perfect! I did change
engines receintly as the Evo 26GT was getting tired. I converted an OPS
Maxi 30 to gasoline ( http://tech.flygsw.org/OPS.htm
) and installed it in the speedster. What a magnificent combination! This engine was a new
but 20 years old!
Mods
for better performance
AIRFIELD
PHOTOS PHOTO PAGE
Official Rearwin
Website
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