RE: Seagull Harmon Rocket
 

Minnflyer,

I can see that in the picture now that you say that. What a great idea. I may just give that a try.

Thanks,

Adam

RE: Seagull Harmon Rocket
 

Adam,

Thanks for the reply. I have my engine mounted, and i'm very close to completion. I think I will go ahead and add some balsa tri-angles to the inner structure of the horizontal stab. I suppose it's more for peace of mind than anything else. We shall see! Thanks again.

RE: Seagull Harmon Rocket
 

Guys mine bit the dust this weekend due to a failure with the horizontal fin...i broke in mid air on its third flight of the day. You could just hear a flapping noise and just make out the left fin flapping and that was it.....plane went into a dive and the rest is history.....big shame as me and this plane had some fun.. good value for money and looks real good on the ground and in the air..im gonner get me the pc-9 now i think.

RE: Seagull Harmon Rocket
 

Well, I started this thread well over a year ago, and finally just got around to buying my Harmon Rocket. Its on its way, and I am looking forward to getting it together and running it through its paces.

RE: Seagull Harmon Rocket
 

You're gonna like it!!! How about a build thread for those folks that don't have one yet? I could see all the things I might have done better.

200+ flights on mine........flies on rails.

RE: Seagull Harmon Rocket
 

After 8 years of building I am back to models.
Finally bought mine yesterday.
I've wanted one since I first saw it in Horizon's catalog.
All my planes are electric, and considering a big 4 stroke for this one - hey if it's not overpowered , it's not a Rocket!
I kinda hate to cut up the cowl though[:o]
May break down and do a conversion - hmmm:eek:

Thanks to everyone for their info and setups. Seems like it could carry some more weight up front 18-21oz powerplant?

Saito 82 or 100 4s seem to be my frontrunners. yep either 4s or electric.

RE: Seagull Harmon Rocket
 

Decided on the satio .82 after comparing the two motors side by side.

Stripped off the covering from the vert stab and elevators.
Will join the elevators w/ a .210 carbon rod and some carbon cloth overlay and use a single high torque servo.

The vert stab seems very strong when I twist and bend it in my hands, but the bending loads are concentrated (mid span) just outboard of where a forward leading edge backup piece of wood ends - which is consistent with the failure photos previously posted. It sure seems strong enough to me - perhaps the choice in linear grain wood is better in this example which is stamped 4000054. And the workmanship under the covering is very good - tight wood joints, consistent radius on leading and trailing edges and plenty of glue used in all joints inspected. The wood seems on the heavy side - perhaps not such a bad thing on this airplane.

RE: Seagull Harmon Rocket
 

A Saito .82 should do nicely, and provide more than enough power for your Rocket. Remember to take some photos.

RE: Seagull Harmon Rocket
 

Break this![:@]

RE: Seagull Harmon Rocket
 

Built up a run-in test stand tonight, so I can get back to the model now.;)

Not bad for an electrics guy, eh?

RE: Seagull Harmon Rocket
 

CG question?
Some guys flew at the aft limits 3.5" and said it felt noseheavy. Stalwart flew 5/8" forward of the envelope and said it flew fine.
Are you guys measuring the cg with a full fuel tank? And then checking with an empty fuel tank to confirm it is still in the range?
Is every one using the stock fuel tank? It looks a bit small to me?

I'm considering a larger tank-dubro 16oz. and if I cg it with tank empty I am at the aft limit and if I cg it full tank I creep forward of the forward limit a bit.

RE: Seagull Harmon Rocket
 

When I put mine together, I went with a 14oz tank, too much fuel. I went back to the stock tank, it flew much better, like a rock with wings. I think I got the only bad one in the bunch. The large tank, and with the cg set forward all the way, I had to have 110% up throw on the elevator to get off the ground. The stock landing gear had to be rebent after every other landing. Mine landed very hot, at about 1/4 throttle, it would tip stall. Moved to the stock tank, much better up elevator response on take off. Started moving the cg back a little at at time, and while the response in the air was better every time I moved it back, the tendency to tip stall worsened at the same time. If I deadsticked at under 100 ft., there would have been no recovery, unless I was already at full throttle. That was the only way the the Rocket would fly for me. My son in law remarked that the smoothest landing I made with it was when it deadsticked at altitude during a loop, I used every bit of 225 ft of runway to bleed off the speed. (It was a sweet looking landing, probably the only time I have every had the prop stop at the 3 - 9 o clock position).. I have never checked the cg with the tank full, only empty. I was using an Evo 46 up front.

RE: Seagull Harmon Rocket
 

Rocketrob,

You won't need the larger tank with the Saito 82, unless you're flying cross country. I fly a 40 size Spitfire with the 82 and one 10 oz tankfull for three 10-15 minute flights at 2/3 throttle and still have fuel left in the tank.

I've just checked the current CG on my Harmon. It is exactly 3.25" from leading edge at the wing root, which coincides with the rear edge of the spar---who'd 'a thunk it. Since removing some weight in the nose and changing to the Evo 52NX, that is where it stands.

The plane deadsticks like a trainer and flies rock solid. It has been flown by a large scale IMAC contestant who remarked that it flew a lot like his Extra 300.

RE: Seagull Harmon Rocket
 

Thanks for the info guys.
I'll probally use the stock tank, but last night I did some weight and ballance checks and currently it is right at the aft limit empty and full fuel moves it forward to 7/16" forward of the forward limit. Would have less cg shift w/ the smaller tank. My electrics experience is showing- put the biggest batterys in - that can cg;)

Bingo, sorry you have had such a tough go at it - your description sounds like the full size plane - not a lot of wing area - and yes if you get it slow she will bite and hard. But add throttle and a big smile grows on your face:D

Stallwart, could you confirm this measurement is with empty tank?

RE: Seagull Harmon Rocket
 

Yes. Tank was empty when I checked the CG.

RE: Seagull Harmon Rocket
 

Thanks Stallwart.

Some progress photos......hope to get her out for maiden tomorrow at Alameda Hornet Squadron - if winds cooperate[:o]

RE: Seagull Harmon Rocket
 

Nice engine installation! I have an 82 in the box and a brand new uncut cowl for the Harmon. A flying buddy is working on this plane with a YS-63 for power. I'll be waiting to hear how the maiden goes. Get some photos, eh?

I noticed servos are all mounted rearward in the fuse with your setup. I assume you've begun checking balance. I have my battery over the fuel tanks and throttle servo where you have your battery in order to get my CG. If I change to the 82, I'll be asking you balancing questions.

Good luck on the maiden!

RE: Seagull Harmon Rocket
 

Well I am hoping to get the YS 63:D I will find out in 2 days if I am going to get it or not!

RE: Seagull Harmon Rocket
 

It has started to rain so it looks like no flying. Well just means more time to work on the rocket!:D

RE: Seagull Harmon Rocket
 

She is comming together[8D]

RE: Seagull Harmon Rocket
 

The pilot is a pinhead but he's got a hottie girlfriend!;)

RE: Seagull Harmon Rocket
 

Great job on the cowl! Do you think you'll have enough exit air area for cooling?

RE: Seagull Harmon Rocket
 

She flew very well. A bit to much power on takeoff, but thats easy to fix[:-]

Left the 16 oz tank in and flew like I had a huge one. In retrospect landed wit very little remaining - must have bee up for 10minutes?

I really like this airplane!

I was so happy when the fuel system worked out so well. i was worried plumbing the fuel fill fitting (in the top of the cowl) and the extra tubing would present problems.

Need to fab new gear......found Funtana carbon gear at Horizon Hobby for $22.95 to hack:D

The cg was set at the aft limits with empty tanks and I noticed no problems landing w/ near empty tanks except the plane flew very slow on final, and felt much lower wing loading than anticipated.

RE: Seagull Harmon Rocket
 

Stallwart - it was a very cool day - record setting lows for us low 40's by the time I was flying.
I want to open up the smiley airinlet and trim back the exit area and around the exhaust pipe as there was some post flight vibration evidence where the pipe exits the cowl.

RE: Seagull Harmon Rocket
 

Glad your maiden went well, and great photos!

I'm surprised your fuel was used up so quickly. Either you're running a new engine on the rich side or you lost all track of time.:D

Those thick wings allow some slow approaches. I forgot to mention that.