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Seagull Harmon Rocket

Old 08-18-2008, 09:58 PM
  #226  
VeeAte
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Default RE: Seagull Harmon Rocket

Thanks ckangaroo.

I dont spose you or anyone else has the instruction manual for this plane?
As I rebuilt the engine mount I need to know how much angle the motor is supposed to have (left,right,up,down) etc.

Sorry for all the questions. I just want this to fly right.
Old 08-18-2008, 10:41 PM
  #227  
stallwart
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Default RE: Seagull Harmon Rocket

I believe you can download the manual from Horizon Hobby's site.

Try this link.

http://www.horizonhobby.com/Products...ProdId=SEA3050
Old 08-19-2008, 01:04 PM
  #228  
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Default RE: Seagull Harmon Rocket

I would have been happy to help, but I sold my Harmon Rocket last year and the manual went with it. The Plane really does fly well. The only thing I really reccomend is replacing the stock landing gear with some of a bit better quality. The gear really does bend to easilly..... even on very soft landings. Other than that the Plane is built pretty well!
Old 08-19-2008, 06:00 PM
  #229  
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Default RE: Seagull Harmon Rocket

Thanks Stallwart I downloaded the manual for the plane.
However the manual has very little on engine installation. In fact it has two pictures and thats about it. []
It does help with the throws etc of the control surfaces tho which is very handy.

I am hoping someone can remember whether there is any right or left thrust etc on the engine from the factory. I have lined the firewall up as best I could with what was left of the nose of the plane, but when I dummy it all up it looks like the motor is sitting dead on square to the fuselage.

Is there any general rule to mounting engines with a certain thrust angle? Or is it different from plane to plane?
Old 08-19-2008, 07:22 PM
  #230  
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Default RE: Seagull Harmon Rocket

Mine came from the factory with correct right and down thrust. If I recall correctly, blind nuts were already installed for the glow engine mount.
Old 08-19-2008, 07:36 PM
  #231  
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Default RE: Seagull Harmon Rocket

Ok thanks.

I had to rebuild the engine mount and I didnt own the aircraft from new. I guess I will have to just use trial and error to find out the best angle to put the engine on.

Thanks for all your help
Greatly appreciated.
[8D]
Old 11-18-2008, 07:30 AM
  #232  
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Default RE: Seagull Harmon Rocket

Well I took the Harmon Rocket III out for her re-maiden today.
I was given the plane by someone who had damaged it in a crash so this was the first time I had flown this model.

The low rates on ailerons as stated in the destruction manual seemed too low for me and the high rates were better suited to being set as the low rate. This is a personal thing I guess.

Rudder needed high rates to knife edge and it only just did it at full deflection. So I upped both low and high rates for the rudder as well.

Elevator seemed fine on both high and low.

Only thing I need to work out now is why I am only getting 4 minutes flight time per tank of fuel.
New SK .50 engine so this may need some time to run in to develop more power so I am not 3/4 throttle and above the whole time. Was very windy tho so may not need so much throttle on a calm day. Although going with the wind didnt seem altogether super fast.

Ran a 12x6 Master Airscrew prop initially, but ended up going to an 11x8 MAS. Thinking of going up to an 11x9 or 11x10.
Old 11-22-2008, 05:00 AM
  #233  
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Default RE: Seagull Harmon Rocket


ORIGINAL: VeeAte
Only thing I need to work out now is why I am only getting 4 minutes flight time per tank of fuel.
New SK .50 engine so this may need some time to run in to develop more power so I am not 3/4 throttle and above the whole time. Was very windy tho so may not need so much throttle on a calm day. Although going with the wind didnt seem altogether super fast.
Funny that you should say that. My own Rocket had a new SC46 in it and I dead-sticked it on the maiden fairly low down. I got it down ok but if I'd any idea that it was almost dry I'd not have been doing a low pass. I must have had about seven minutes. I lost it after a few flights due to a loss of radio contact. I'd like another one but the thought of such short flights puts me off. On the other hand, the OS 46LA in my Tribute 36 will easily run for twenty minutes mostly WOT. Surely we can't have the engines set up properly. What's anyone else's view on such short flights ?
Old 11-22-2008, 05:14 AM
  #234  
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Default RE: Seagull Harmon Rocket

Actually I got it sorted.
Went out and set the needles back to default and started again.
What was happening previously is while holding the plane vertical in my hands at idle for a few seconds then punching the throttle it would die. So originally I had richened up the high speed needle to overcome this. What I should have done is richen up the low speed.

So I reset the high and low speed to default. Then set it up about 3-4 clicks rich on the high end at WOT.
Then I held the plane vertical for a few seconds and punched the throttle. It died a few times til I had the low end set rich enough so it didnt die anymore doing this. Then I reset the high speed again (adjusting one throws the other out).
Double checked that it would'nt die holding it vertical a couple of times. And now I can get 9 minutes with still about a third of a tank left as long as I am not at full throttle constantly. Going to set the TX timer to 10 and will keep an eye on the remaining fuel after each flight.

But this plane still seems really draggy. Maybe cause it has a fairly "fat" wing? ie: the airfoil is thick.
It may be the engine I am using as its an engine built for torque not revs. My high wing trainer with a OS 46AX is faster. By a fair amount.

This week I am going to swap the engines over and see if it makes any difference.

Failing that I am going to put my OS .70 Surpass II in it and see if that helps.

Also does anyone else notice this planes rolls out of the top of loops on high rates?
Mine will roll to the right out of the top section of a loop with a lot of elevator. Maybe I should just drop the rate down for the elevator on high?

Also need to setup some mixing between rudder and ailerons too I think. If left wing is down and canopy towards me it will move away from me. Towards the wheels. And I have to hold a bit of right aileron to stop it rolling onto its back.
So maybe both rudder-aileron and rudder-elevator mix?

New to all this.

Old 12-08-2008, 07:57 AM
  #235  
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Default RE: Seagull Harmon Rocket


ORIGINAL: MormonMike

The Enya .50 is about the only engine that will fit WITHIN the cowl parameters. You will need a pitts type muffler and mount the engine at a ninety degree.
(Old thread, but maybe useful to someone )

Not entirely true - I've got a SuperTigre .60 2 stroke in mine. The engine fits in beautifully on a 90 degree angle, leaving the needle valve poking out the top of the cowl and a small hole in the side to poke your glow driver through (or you could mount a remote glow adapter or an on-board glow driver if you're really keen). The only issue I had was getting the Bisson pitts style muffler in - I had to cut two holes in the underside of the cowl for the front "corners" of the muffler to poke out of. You could probably get around this by using a Slimline muffler instead, however you can't really see it when it's on the ground (it's underneath of course) and it moves WAY too fast in the air to notice due to the .60 engine and 13x6 prop. FYI with that engine and the rudder servo mounted up front with a pull-pull system I've needed zero lead to balance it, and it lands almost as easily as my old trainer did (before I put twin engines in its wings and flew it into the ground when the vertical stab snapped off, but that's another story).

Matt

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