Sig Kobra engine question.
 

I have been flying my kobra for some time now, on a OS .25FX. Was wondering does a Tunder Tiger .36 pro fit if so has anyone out their tried this combo?

RE: Sig Kobra engine question.
 

A TT 36 Pro should fit fine, it is only slightly heavier than the 25 and has way more power. Should make for a wicked combination.

If you want a drop-in replacement, the OS 32 is the same case size and mounting bolt pattern as the 25, weighs slightly LESS than the 25 and has pretty much the same power as the TT36 Pro. It is a great all-around speed/sport engine and works well with the stock muffler as well as fantastically well with a Jett or Ultrathrust muffler, a mousse can pipe or a full tuned pipe.

Either the TT or the OS are great engines and you really can't go wrong with either one on a plane the size of the Kobra.


Mark

RE: Sig Kobra engine question.
 

As mentioned above the 32 is a good replacement-if your bold try the TT pro46 or OS 46AX with a 9x8 or 9x8.5 prop-WOW

RE: Sig Kobra engine question.
 

Frenchie,

I'm doing exactly that, i.e., I have a fairly new 46AX with a MACS Muffler (mainly for weight savings). I'm noticing some significant differences in the wing build as compared to other kits I'm done (US60, Ultimate Bipe, Supersportster 40, etc.) Every plane I've ever built joins the wing halves on the #1 ribs, this plane differes from that. Also, there is no plywood doubler at the center of the wing...

What suggestions can you offer to ensure my plane doesn't desitigrate on initial flight?

Any tips on Tail dragger setups?

RE: Sig Kobra engine question.
 

cptcrust1,

You may want to PM Gray Beard about his Kobra as well, he used a hot rodded Webra 55 on it and it was built for pylon racing:

http://www.rcuniverse.com/forum/m_66...tm.htm#6686936


Mark

RE: Sig Kobra engine question.
 

Gray Beard was actualy reviewing the thread (said he was logged in) when I read your post. I sent him an email. Hopefully he's read this post and will grace my humble building skills with some wisdom and advice (flattery will get you everwhere... LOL)

Crusty.

RE: Sig Kobra engine question.
 

I forgot to mention that his racing version was absolutely gorgeous and the nicest representation of a Kobra I have ever seen. It made me think about getting one for a TT36 Pro I have laying around...

Mark

RE: Sig Kobra engine question.
 

I am running a TT pro .36 in my Kanke F3d plane and love it. I added an Ultrathrust muffler and am running an 8-8 prop at around 19,000 rom. The TT .36 will be cheaper than the OS but do not know the differance in performance. The TT is also a direct swap for the .25 FX. That should be a great combo.

RE: Sig Kobra engine question.
 

Glad to hear that. I really enjoy using Thunder Tiger engines. For the price it doesn't get any better. My kobra can be seen at our clubs picture site www.coastalplanesrcclub.com/gallery

RE: Sig Kobra engine question.
 

Man I'm sorry I don't remember off the top of my head. Grey beard gave me the inspiration for a tail Dragger which you should consider due to weight. It is really a fast little plane that handles real well.
I have had no problems with the wing-it is a pretty tough plane.

RE: Sig Kobra engine question.
 

WOW!! Great shot of the wing. I was thining of fully sheeting the wing for extra strength. Do you have any shots of how you did the servos? I'd love to duplicate that....

RE: Sig Kobra engine question.
 

OK, I will chime in. I took all these photos out of my puter so I couldn't remember A lot about all the little things I did to it so really wasn't A lot of help.
It is A taile dragger but not exactly. It has A skid on the back, I didn't bother with the wheel or anything. All this one has to do is take off and get back on the ground. The pit man runs out and gets it for the pilot and holds it down on the runway nice and straight.
The one big thing is to install the elevator and rudder servo all the way back and I had to hatch the bottom of the fuse so I could get at them and the battery.
I did have to mount the engine and build the cowl around it, drill holes so I could get at the mounting screws. That engine and muffler are A very tight fit.
It's an easy build so just look at it as you go along and think about the stress points. The wing is very strong and the wing mount adds strength to the wing saddle area so no real problem there at all.
It's really fast but there are better designs for going around the pylons. Maybe I can get some shots when the race season starts.

RE: Sig Kobra engine question.
 

check this thread also

http://www.rcuniverse.com/forum/m_33...tm.htm#3481849

RE: Sig Kobra engine question.
 

That's too funny, I had to enlarge that photo and do A double take. The photo looked like it was taken in my old shop. Before I moved I had A 1000 sq ft mobil home for my shop/hanger and that looked like the kitchen where I did the balancing. I used the laundry closet for my spray booth for painting.
That was A good Kobra thread with some good looking planes.

RE: Sig Kobra engine question.
 

Gary,

When I saw your thread, I thought you two were the same guy.
I thought what's the chance of two guys, both doing
red Sig Kobras using racing wheels? I had to lookup some old
email of GarySS to be sure. GarySS emailed me some details and
a few pictures of his Kobra. He used racing wheels also. He painted
the gear wire and wheel gray and called them poor man's retracts
as they seem to disappear when flying. Here's a couple more photos
of GarySS Kobra. (correction made)


iflyg450

This is a quote from GarySS email.

"With the TT .36 and a Master Airscrew 10x6 prop the vertical capability
was out of controllable sight".


Ron

RE: Sig Kobra engine question.
 

Ha!, nice seeing pictures of the old bird again! I finally sold it this year to a good home. She has joined the Army and should be flying somewhere on the east coast. The new owner reports he is really enjoying it and it tracks/flies like an arrow with the original TT-36. That was my best 2 cycle engine and a good match for this airframe. Best Regards.........GarySS

RE: Sig Kobra engine question.
 

I hope these help-if you need anything specific let me know.