SU-26 50CC - 87.5" from Nitroplanes.com Question

[wecoyote]

Any one build this plane? I'm considering it to put my Zenoah 445 twin in.

http://www.nitroplanes.com/su50giscniga.html

Does any one know if this engine will fit inside the cowel? Specs say it's for a 50 to 80 cc engine (3W recomended) so powershould be plenty. Just want to know if it will fit before buting the plane.

Thanks.

[vsnap]

80cc too big for the plane....50cc -60cc is a better range...Ask me how I know

[wecoyote]

	Quote: Originally Posted by vsnap
	80cc too big for the plane....50cc -60cc is a better range...Ask me how I know

Ok, I'll ask.....How?

The Zenoah 445 is actually 73CC. They over bored the 445 to make the 80CC engine.

[SleepyC]

Because they carry a version of that plane that is of a much higher quality!
But has ruffly the same dimensions.

If your looking at that plane, and want a quality version with GREAT customer support, check out his site.

www.dawghouserc.net

Remember, you get what you pay for.

[bobzilla]

This plane is listed as an 87" for the 50cc to 85cc. There is no way this arf can support the weight and thrust of an 85cc engine.

The fuselage does not have a tunnel for pipes. The front motor mount is NOT attached and is supplied so that you can mount various motors.
The center of fuselage has 2 cutouts already for dual rudder servo pull-pull. The hardware kit includes pull-pull cable and servo arm for 1 servo.
The wings, tail hinges are robarts and are pre-drilled. The landing gear is fiberglass formed and painted.

The manual for the plane shows the DA-85 as the preferred engine for this arf.
See attached scan of the manual for intall of DA-85.
It also says recommended MTW 100 cannister with headers..and THERE IS NO TUNNEL IN THIS ARF..for cannisters to fit.
If you look at the manual closely, you can see the DA-85 is with a PITTS style muffler.

I think the DA-85 would be way over-powered and too heavy to properly balance the plane. The plane looks and smell 50-60cc..but not 85!
There is no metal brackets on landing gear attachment blocks, and only double ply (1/8" on sides of motor box and a 1/4 ply front mount. This is far
too weak to support the power and weight of a 80-85cc motor. The plastic hatch is weak and mine was cracked upon receipt.
I think this plane would sing with a DA-50 or 3w55 or even an EVO 58.
The distance from motor box to front of the cowl is 6 7/8" to 6 3/4" depending how much cowl you want to overlap the hatch front.
With 3" standoff on my DA-50 and a spinner backplate, the prop should clear the cowl fine.
There is no plywood ring inside the cowl, like you find in many YAK arfs. Attachment is via bolts thru cowl to hardwood block with blind nuts on fuselage.
Axles are bolts, which I will be replacing with titanium axles.

*** WARNING ***
After reading the manual, it is very evident that the supplied manual is NOT the correct manual that should have been supplied with this ARF or it is erroreously written in many areas.

There are many inconsistanties and here I will mention a few:

1 - Landing gear installation is completely different from the text vs the supplied pictures/hardware. Supplied hardware is bolts and two different types of nuts that screw on the axle BOLT. The text in the manual talks about wheel collars, filing flat spots on axles. The reference to installing the gear says to use
4 socket head screw and 4 lock nuts..when in fact..the gear uses 5 screws and has blind nuts installed in the fuselage (it would be impossible to use
lock nuts as you could not get your hand nor a wrench to that area.
2 - The installation of the switches show in the pictures a completely different fuselage with pre-identified locations to mount the 3 switches. There are no
such locations on the fuselage.
3 - The maunal provides no info or directions on mounting the front hatch pins. The manual also says to install the blind nuts on the hatch rearward tabs..but this is already been done at factory.
4 - If you look closely at the motor box area in the pictures..you will see it is a completely different motor box and surrounding area. (See my scan of motor box vs my pictures).
5- The pictures in manual show a completely different tank mount surface (platform) than what actually is. There is no predefined mounting platform nor one supplied. No pictures/text exist on how to assemble the tank hardware nor mounting.
6 - Page 8 of manual (elevator servo installation), Step 1 says to intall the elevator servo into the stabilizer, which is not the case. The servo is NOT INSTALLED in the elevator, but on the side of the fuselage. Page 13 actually repeats this process correctly (Stabilizer installation), but is completely void of any installation of the carbon fiber anti-rotation pins.
7 - There is no mention in the manual on how to install any of the robart hinges, nor any assembly pictures/text for this. Althought this is common hat to many who have used Robarts hinges before, a beginner needs and should be instructed on these hinges properly.
8 - There is no centering marks on motor box front plate, nor any template. The template shown in manual being used to mount a DA-85 is not supplied.

I would use common sense when building this ARF and do not rely on this manual as being even close to accurate.

Hopefully, NitroPlanes will produce a better and more accurate/complete manual in the near future.

I also found that the factory did not cut the ultracote(?) and seal around the huge slots that the wings slide into.
To tack the coating down..I used some stixit and a small iron and folded the coating back under the side panels.
I have never had a plane where this was NOT ALREADY done! If you look at the attached picture from Nitro website, it is obvious
that the slots are just covered over. (see green circle) If you do not do a good job of tacking the coating down..I would expect
the coating to start peeling after numerous wing removals/attachments.

Bobzilla
www.thebobzilla.info

[Mithrandir]

but how does it fly?

[wecoyote]

Thank you Bobzilla!!!!
Everything you mentioned is easily overcome. I have built MORE than my share of planes over the years.
I'm just looking for something new to stick my engine and radio gear in and torture the sky with on weekends. I ain't no IMAC contender nor do I aspire to be. Just like to fly around .

Could you please measure the inside diameter (side to side) of the cowel for me?

Thanks.

[bobzilla]

I am like you..I just want a cheap egg beater for my parts also..
the cowl is 11.5"..plus/minus a smiggen..because the dang thing is warped bad..and flimsy.

[bobzilla]

	Quote: Originally Posted by Mithrandir
	but how does it fly?

I don't think anyone knows yet..as it is quite new to market (couple weeks) and I won't have mine finished till this weekend. I can say this....the wings are great..and the tailfeathers..are also great..lots of throw..and surface..I expect this to be a great flyer..that is if the manual guessed the CG right...based on what other screw-ups are in the manual..i will probably just set the CG to where I THINK it should be and fly it.

bobzilla
www.thebobzilla.info

[jfstrama]

My extremeflight Yak didn't have the covering for the wing slots cut, but did have a very accurate set of instructions for cutting the covering and sticking it down well.

I just recently built a 50cc yak ARF that looks suspiciously like the magichand instructions (the instructions in the box were for a completely different plane!) and it didn't have the covering removed from the wing cutouts either.

So I wouldn't say that all of them have that done.

The 50cc Yak had junk hardware that I replaced with dubro and hangar-9 titanium links I had lying around (the MagicHand ones looked to have nice hardware in the instructions by comparison)

Leave yourself an 1/8 to a 1/4" of covering and slice through it to get into the tight raduis corners and hit it with an iron. Mine (on the extreme flight) has not come loose in over a year.

MadDog Joe

[bobzilla]

	Quote: Originally Posted by jfstrama
	My extremeflight Yak didn't have the covering for the wing slots cut, but did have a very accurate set of instructions for cutting the covering and sticking it down well.

I just looked at the extremeflight manual for that yak..and one HUGE difference...your yak, like many others have balsa the fills the area in question..(kinda like a shelf that goes all around the opening inside. This NitroPlanes arf does not have that..just the bare frame..alas..to tack the coating down..you
have to tack 180 to the back side..and you can only access with a small iron..'
I am gonna coat the backside with stixit..first to hope to get a good tack.

bobzilla

[wecoyote]

Thanks!!!

Quick measurments on my engine measuring a 5 3/4" radius from the crank shaft looks like I would have about 1/2" clearance on my spark plug boots. Everything else has plenty of clearance.

[jfstrama]

	Quote: Originally Posted by bobzilla
	I just looked at the extremeflight manual for that yak..and one HUGE difference...your yak, like many others have balsa the fills the area in question..(kinda like a shelf that goes all around the opening inside. This NitroPlanes arf does not have that..just the bare frame..alas..to tack the coating down..you have to tack 180 to the back side..and you can only access with a small iron..' I am gonna coat the backside with stixit..first to hope to get a good tack. bobzilla

Bobzilla,

That I didn't know. Even the $200 50cc Yak had the balsa fills, so you are right, that is a bit strange.

Of course, you could always add the balsa fills (granted that would suck). How's the build going? On the cheap yak everything went fairly well until balance time, it is way tail heavy! I guess I was supposed to use a cheap engine with magneto not the da-50 to make it balance. I ended up with dual 6V 4200mah nimhs and a 4.8V 4200mah ignition battery in the nose with another 4oz of nose weight. So light weight performer it ain't gonna be.

MadDog Joe

[vsnap]

Ooops not like my Sukhoi. I was thinking of a different company Sorry...I can attest that all your talking about is done on my sukhoi. An 85cc engine is way overkill on this size plane unless it is very heavy. Mine came in at 16lbs and a 3MM 53cc on stock muffler hauled it around like nothing.

[wecoyote]

bobzilla,
Did you get your's finnished? Hows she fly???