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Nitro models pusher Bobcat?

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Old 03-26-2007, 03:27 PM
  #1376
gofastz
 
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Default RE: Nitro models pusher Bobcat?

Another couple of weeks and the Jett 60 we'll be here!!!!!!
I had some request for photo's of the wing attachment and my attenna rigging, so here they are...note in the pictures it shows the tank secured with a cross support. I used a control rod tube to run the attenna the length of the fusalodge and secured it with thick CA to the support just under the lip of the canopy opening....also, the trailing edges of the wing are secured with main landing gear strap tabs...I saw this in this forum and copied it....It works great and will allow removal of the wing when needed.....Please note that I take no credit for all these great modifacations as this forum was were I got them from....It goes without saying that there are some great builders here and as this is my first time using this forum I am honerd to exchange some of you great ideas and to be able to use them......


Mark
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Old 03-26-2007, 06:38 PM
  #1377
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Default RE: Nitro models pusher Bobcat?

Thanks Mark.

Those pictures will be very helpful for me.

Chris
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Old 03-26-2007, 08:58 PM
  #1378
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Default RE: Nitro models pusher Bobcat?

Quote:
I'm particuarly interested in how you're routing the antenna.

Aero D,
Seen your question and thought I'd offer my method. I glued a 27" length of nylon tube into the front section of one wing and threaded the stock antenna wire into the tube. There is an oval shaped hole in the ribs close to the leading edge that runs all the way down the wing. It's pretty easy to thread the tube into this area and secure the end to the inside of the root rib with a small piece of light ply leaving a short stub of the tube to protrude into the fuse when the wing is attached. The 27" length of tube is more than enough with the receiver just behind the nose gear mount.
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Old 03-27-2007, 01:03 AM
  #1379
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Default RE: Nitro models pusher Bobcat?

There has been some canopies that have been damaged that nitro is slow in getting in stock.....you guys might try this to get back in the air......
1. Make a mold of the canopy as closely to the orginal by using a balsa block..
2. When your satisfied with the mold, take a empty coke or what ever liter bottle and cut it into a flat sheet...be sure to romove the label...
3. heat the oven to about 150 degrees, place the sheeting on a pan with aluminum foil.
4. When the sheeting is soft and plyable take the mold you made and streach it over it to produce your new canopy.
5. Allow to cool and cut access material from bottom to match ....
6. Don't worry about scuff or prints as you form the mold as you paint the canopy to your likeing...( I like black or smoked)

Hope this helps..........Mark
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Old 03-27-2007, 07:03 AM
  #1380
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Default RE: Nitro models pusher Bobcat?

Stick,

Thanks for the input. So in your method, is any of the antenna wire exposed outside of the plane?

Chris
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Old 03-27-2007, 03:13 PM
  #1381
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Default RE: Nitro models pusher Bobcat?

Re-thinking this whole CG thing.........

Guys I got tired of fighting the muffler problem and put a Pitts style muffler on the Tower .75 as others have done. The plane flew absolutely great untill I tried to land. When I cut the power it dives for the deck like a thirsty earthworm. I managed to save the plane, I made a go around and tried to control the landing but it hit hard and broke loose one of the main gear mounts. It bounced and I mean high and the prop was damaged in the intial hit so I was committed, I pointed the nose at the ground and gave full elevator before impact and it settled on the runway light as a feather...got a standing "O" for that one. With the Pitts it changed my CG to about 10.75 so I am wondering if this behavior might just be the Bobcats way of letting me know its tail heavy. The only thing is I would expect it to mush and tip stall instead of dive for the deck and it shows none of this behavior at speed???? Maybe this is a jet thing, this is my first Jet type glow model. Any input is appreciated.

Gotta go buy some more underwear.
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Old 03-27-2007, 03:31 PM
  #1382
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Default RE: Nitro models pusher Bobcat?

Maybe it's a Motor incidence thing - I noticed the same thing with my plane. Chop throttle, and it dived, big time. I was wondering if I needed to change the give the engine a little more downforce, or upforce - something like that.

Mark
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Old 03-27-2007, 03:40 PM
  #1383
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Default RE: Nitro models pusher Bobcat?

One for motor incidence... increase down thrust...
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Old 03-27-2007, 04:09 PM
  #1384
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Default RE: Nitro models pusher Bobcat?

Aero D,
No, none of the antenna wire is outside the plane. The 27" tube runs from the root to the tip and is more than long enough for the wire.
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Old 03-27-2007, 07:34 PM
  #1385
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Default RE: Nitro models pusher Bobcat?

having the same problem but trying to fix it. after you fly your plane and trim it out for hands off I landed the plane and notice the elevator trim is upward. Checked the incidence with the wing and stabalizer and it had 0 incidence. I added shims to raise the incidence to almost 1" and now I can almost do hands off landing with just killing the throttle. It still has alittle up elevator so going to shim it up a hair more and try again. my final CG is 9 5/8. I can do hair pin turns now without stalling it.
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Old 03-27-2007, 08:19 PM
  #1386
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Default RE: Nitro models pusher Bobcat?

Contryshooter,
I am new to the hobby. What do you mean you added shims to raise the incidence to almost 1" ?
Michael
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Old 03-27-2007, 08:32 PM
  #1387
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Default RE: Nitro models pusher Bobcat?

I think he meant one degree, not one inch
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Old 03-27-2007, 08:36 PM
  #1388
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Default RE: Nitro models pusher Bobcat?

Crazy4flight,
how would you do this ?
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Old 03-27-2007, 08:44 PM
  #1389
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Default RE: Nitro models pusher Bobcat?

Aero D,

I took stick jammers advise on running antenna through tube in wing.
Worked out great, and fairly quick/painless. By the way, thanks for the idea stick jammer!
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Old 03-27-2007, 08:52 PM
  #1390
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Default RE: Nitro models pusher Bobcat?


Quote:
ORIGINAL: P 51 MAN

Crazy4flight,
how would you do this ?

I would believe that countryshooter, is adding shims between the tailbooms and the wing at the rear bolt.
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Old 03-27-2007, 08:54 PM
  #1391
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Default RE: Nitro models pusher Bobcat?

no. I put about 1/4" shim under the stabuilizer arm that connects to the wing, on each side the back end of the wing is about 1" lower then front and the stabilizer is even front and back. I dont know what degree it is. yes I mean the tailboom and wing.
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Old 03-27-2007, 08:59 PM
  #1392
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Default RE: Nitro models pusher Bobcat?

Thanks for the information. Can you show some pictures ?
Quote:
ORIGINAL: countryshooter

no. I put about 1/4" shim under the stabuilizer arm that connects to the wing, on each side the back end of the wing is about 1" lower then front and the stabilizer is even front and back. I dont know what degree it is. yes I mean the tailboom and wing.
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Old 03-27-2007, 09:15 PM
  #1393
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Default RE: Nitro models pusher Bobcat?

ok will try to post tomorrow
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Old 03-27-2007, 11:18 PM
  #1394
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Default RE: Nitro models pusher Bobcat?

Quote:
ORIGINAL: NM_Mark

Maybe it's a Motor incidence thing - I noticed the same thing with my plane. Chop throttle, and it dived, big time. I was wondering if I needed to change the give the engine a little more downforce, or upforce - something like that.

Mark
That is a good thought but this problem developed after I put the Pitts on which modified the CG, until then it landed like a dream.
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Old 03-28-2007, 12:49 AM
  #1395
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Default RE: Nitro models pusher Bobcat?

I have just finished assembling one of these with a gms 76, a pitts muffler and 11X7 prop.
I just switched to the pusher prop and seem to have trouble keeping the engine running.
I cant get the needle valve set correctly before the engine starts cutting out.
Seems to be overheating. Engine runs great with a regular prop on it (problem is it would fly backwards) hense the pusher prop...
any suggestions?
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Old 03-28-2007, 04:55 AM
  #1396
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Default RE: Nitro models pusher Bobcat?

Is the pitts muffler the right size for the engine? try the stock muffler and see if that helps. had the same problem when I tried a pitts style. think it had too much back pressure on the engine.
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Old 03-28-2007, 07:22 AM
  #1397
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Default RE: Nitro models pusher Bobcat?

I first started with a Tower Hobbies .75 with a Pitts muffler on my Bobcat, and had no problems at all like that. GMS and Tower engines are identical. Seems you're just leaning the engine out too much.
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Old 03-28-2007, 11:17 AM
  #1398
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Default RE: Nitro models pusher Bobcat?

Quote:
ORIGINAL: mkndls40

I have just finished assembling one of these with a gms 76, a pitts muffler and 11X7 prop.
I just switched to the pusher prop and seem to have trouble keeping the engine running.
I cant get the needle valve set correctly before the engine starts cutting out.
Seems to be overheating. Engine runs great with a regular prop on it (problem is it would fly backwards) hense the pusher prop...
any suggestions?
What is the history on the engine is it possible it is not completely broken in yet? Sounds like the case to me, these symtoms match up with that diagnosis perfectly.
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Old 03-28-2007, 03:36 PM
  #1399
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Default RE: Nitro models pusher Bobcat?

I had the same problem with a Mark 61 overheating and leaning out after 3 minutes of flight every time . I cured this by bumping up the nitro content. Nitro actually has a cooling effect on the engine. I have flown it no fewer than 15 times like this with no problems. For you guys having problems landing, this plane will fly very slowly and I have found it lands great at low speeds. It really doesn't have a bad stall characteristic at all. Just give youself plenty of elevator throw with plenty of expo and you'll have it made. I also installed a Fults dual wire nose wheel which works great. Let the plane burn off as much speed as you can in the air. Enjoy
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Old 03-28-2007, 04:57 PM
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Default RE: Nitro models pusher Bobcat?

Quote:
By the way, thanks for the idea stick jammer!
You're welcome, glad it worked for ya. Did your range problems go away?
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