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Seagull Piper Twin Comanche

Old 05-11-2012, 09:52 AM
  #51  
nioa
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Default RE: Seagull Piper Twin Comanche

I'm really looking forward to that Craig. I'm hoping to get mine done this weekend. All the best to you on your maiden, good luck!

Nick
Old 05-11-2012, 10:06 PM
  #52  
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Default RE: Seagull Piper Twin Comanche

Maiden day was a success, didn't have any problem with the finished weight of 5.9Kg without fuel. Did require a fairly generous amount of down trim which could indicate more down thrust may be required on the engines but I will carry out further trim tests once I have some more flight time on her.

She raised a lot of interest from fellow club members and have to admit, I was a bit nervous with the audience. It seems everyone but the pilot enjoys a maiden flight........

Was also happy with the lighting system, even on our bright summers day, lights were still visible. I imagine they will be spectacular in the late afternoon.

Well, I promised photos, so here they are........ Unfortunately, I didn't have anyone to do video but will try again next time she fly's.

Craig
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Old 05-11-2012, 10:13 PM
  #53  
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Default RE: Seagull Piper Twin Comanche

Some more maiden day photos

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Old 05-11-2012, 11:07 PM
  #54  
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Default RE: Seagull Piper Twin Comanche

WOOOHOOOOO !!! [8D]

looks really fine. superb flying attitude.

I do agree for downthrust : photos show very little.

BTW : what about the flying speed ??? looks the .46's are giving a lot of power.

Alain
Old 05-12-2012, 12:32 AM
  #55  
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Default RE: Seagull Piper Twin Comanche

46's are heaps Alain, didn't need full throttle except for pulling through loops, running 11x6 APC props

Craig
Old 05-12-2012, 08:28 AM
  #56  
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Default RE: Seagull Piper Twin Comanche

Fantastic Craig!

A real head turner. So happy that the maiden went well. Gives me confidence that the electric version will fly well too.

Nick
Old 05-13-2012, 01:55 PM
  #57  
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Default RE: Seagull Piper Twin Comanche

She certainly does look good Nick, judging by your early estimates it looks like your total flight weight will be less than 5.9Kg on the electric conversion so you should definitely proceed with confidence

At this stage, I'm pretty happy with centre of gravity at 110mm from the leading edge measured at the fuselage. I notice that there was a correction label stuck in my instruction manual for this measurement.

She's only had 2 flights so there is still some stall testing, trim testing etc to do but that COG of 110 is a great starting point, once trimmed for straight and level, she only required slight down elevator while inverted and only minor down input to maintain level during the inverted section of a slow roll.

Now, I have a question for you.........
I notice from your gear door conversion that you are using the Assan Sequencer. I always do a bit of internet research on products before I buy them for the first time (I find it saves a few mistakes) anyway, I found that people are having trouble with the Assan when it powers up because it does not remember its last state at shutdown. So every time they power up, they have the problem of the gear retracting (even if they bind with the gear down) Obviously, it's not great to have the gear retracting with the model sitting on its wheels every time you turn it on.

I found another discussion where Assan recognised the problem and said that the engineer had ben notified and the issue would be fixed "in future"...........

Are you seeing this problem with yours?????? I'm just wondering what "future" is. I really don't want to buy one and have that problem.

Thanks
Craig
Old 05-13-2012, 05:19 PM
  #58  
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Default RE: Seagull Piper Twin Comanche

I've thoroughly tested the Assan Sequencer and it does not behave like that.

To be sure, I ran every scenario I could think of to see if I would have problems. I did this on a "test" bed that had the actual retracts, receiver, and sequencer running. The doors and nose gear were separated to prevent crashes. Sorry to report that I did not have any thing interesting happen.

In order to arm the Assan you have to flip whatever switch you have assigned to it, up and down, three times. So if your transmitter switch is in the wrong position at "start-up", nothing of course happens, until you arm it. Then you have full control.

The only "odd", undocumented, behavior I have found is that when you first power it up, one of the doors will move about 5 degrees. I think this is the way of it telling you that it has power and is ready to be armed. Once you arm it, the door returns to its correct position. Other than that, I have no complaints. I think they fixed it.

<hr />
I am just about ready to put her in the air. I just have little things to do like the trim, decals, and other small details. The electronics check out, and she is functional (so far, I haven't accidentally hit the gear switch and dropped it yet). I also have to update my thread at RCGroups, so I'm a little behind.

I'm hoping Tuesday morning will be a go. It is supposed to be very hot (106 F), so I will have to fly at 5:30 am.

I'm very interested in what you find, so I will be reading this thread in the meantime.

Cheers,

Nick
Old 05-14-2012, 02:04 PM
  #59  
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Default RE: Seagull Piper Twin Comanche

I have the completed weights for the Electric version:

Air frame = 4775g = 168.4 oz = 10.5 lbs.

plus Two 4S 5000 mAh 25C Lipo's = 1082g = 38.2 oz. = 2.4 lbs.

plus Two A123 1100 mAh batteries = 202g = 7.1 oz. = 0.4 lbs.

Total Air Up weight (AUW) = 6059g = 213.7 oz. = 13.4 lbs.


Old 05-14-2012, 02:24 PM
  #60  
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Default RE: Seagull Piper Twin Comanche

Craig, you were discussing connectors a while ago. Here is what I used:



The header board has two headers on it for each of the wings. One header is obscured by the wing connectors shown, but it is underneath. To connect my wing, I just have to plug in these two connectors, my motor battery, and I am ready to fly.

You may wonder why I have V+ and VR. There are two LiFe batteries. One provides receiver power, and the other provides power to the Retract circuit. The retracts really have a "jolt" when activated. The separate battery prevents that power surge from affecting the receiver.

Nick
Old 05-15-2012, 05:26 AM
  #61  
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Default RE: Seagull Piper Twin Comanche

Hey Nick,

thanks for the info, I have ordered the Assan Sequencer now just waiting for it to arrive, nice solution on the wiring, I will have to look at what I can do with mine.

I expect to get a few more flights in on Saturday so if we get a nice day with minimal wind, I should be able to get a better feel on the trims and setup.

Craig
Old 05-22-2012, 03:00 AM
  #62  
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Default RE: Seagull Piper Twin Comanche

Received the Assan Gear Door Sequencer today. Found a couple of E-Sky EK2-0508 8 gram micro servos that I had sitting in a drawer and decided to get on with the modification

Before and after photos tell the story but as you can see, I was able to use the original spring attachment points as the control horns. Pushrods are simply Z Bends on both ends with one offset front side and the other offset back side so they clear each other.

YouTube Video is here


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Old 05-22-2012, 09:24 AM
  #63  
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Default RE: Seagull Piper Twin Comanche

Don't you just love those "Z" bends!. Glad your sequencer is working out, Craig, and nice video.

I too have to get that down-thrust issue ironed out.

Nick
Old 05-22-2012, 01:35 PM
  #64  
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Default RE: Seagull Piper Twin Comanche

thanks Nick, I am not overly concerned about the down-thrust issue at this stage, I am able to trim and fly as it is and only notice the pitch change when dropping the RPM for landing. Since I will have to program some elevator trim for flaps, I'm going to start with that and see how it goes.

I would suggest for anyone else, leave the cowls off and test fly to get the down-thrust right before shaping and fitting the fibreglass.

Craig
Old 05-25-2012, 01:15 AM
  #65  
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Default RE: Seagull Piper Twin Comanche

Update on final trimming.

Well I had a great day at the field yesterday, a little overcast but hardly any wind. Spent a bit of time on tuning idle mixtures to get both engines accelerating consistently and together then spent the rest of the day and about 3 litres of fuel flying and finalising control trims, Once I had everything the way I wanted it on the primary controls, she was straight and level on anything above about half throttle, below half throttle she definitely required a bit of elevator input to maintain level flight.

However, from a scale perspective, below half throttle was too slow in my opinion so I made the decision that I will not be modifying the down thrust.

What I have done is to set up my flaps using the "Flap System" settings on my transmitter (JR DSX9). By setting the auto land system to active on a throttle of 50% and a delay of 2.0 seconds, I can now flick the flap switch at anything above 50% throttle and nothing happens, then as I reduce power below 50%, the flaps automatically start to deploy at a slowed rate that takes a full 2 seconds to reach full flaps. I did not require any down elevator mixing to arrest any flair tendencies as the model naturally wants to sink as i reduce the throttle down anyway.

The result is that I now use that 2 second deployment time to gradually reduce the throttle and let her settle into her glide path for landing or hold a touch of up elevator for slow flyby's.

The comments from the few people who watched the flights after I had her all set up were very complimentary and I even had someone trying to buy her from me hahahahaha.

Well, that convinced me that I'm on a winner with this setup and so I wont be changing the down-thrust at all. My job is complete, now I can just get on with enjoying her flights. I hope you are all as happy with your Twin Comanche's as I am with mine.

Sooooooo................... what shall we build now

Craig
Old 08-10-2012, 02:16 AM
  #66  
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Default RE: Seagull Piper Twin Comanche

Great plane,

Can someone tell me the width of the Nacelles?

I will put the saito fa90T inside, but this engine is 17 cm wide.
So the question...does it fit in ?

If it does...wow....two saito twin engines....what a sound...

Thanks,

Kor
Old 08-10-2012, 03:09 AM
  #67  
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Default RE: Seagull Piper Twin Comanche

Hi Kor,

the nacelles are approx 140mm wide, the 2 Stroke 46's just fit, your 4 Strokes will require cowl cutting for the head and rockers. I do agree that the 4 Strokes would sound great but having said that, the Comanche looks great flying at speed and the 2 Strokes are not out of place.

The general opinion at the club is very positive and I'm more than happy with my decision to stick with the 2 Strokes.

Whatever you decide, I'm sure you'll love the plane.

Craig
Old 08-10-2012, 04:16 AM
  #68  
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Default RE: Seagull Piper Twin Comanche

Hi, Korvette

Awful idea : just compare the weight of a single .72 with your .90 Twins ...

the answer is here

ahhhh ... if the .60 twins were neot so heavy, it could have been a nice idea !

or try a couple of Vintage ROSS .60 Twins ....

Alain ( who uses " only " a couple of OS FS56 aboard .... )
Old 08-10-2012, 04:18 AM
  #69  
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Default RE: Seagull Piper Twin Comanche

ok thanks.

I have the twin comanche from TOPP.....and its a litte smaller....buth the width of the nacelles is 16 cm...so then only the cilinderheads are comming out.
https://ssl-id.de/rc-tronics-topp-ri...c9uuhvftro0l62

Now I am flying withthe H9 twin Otter with 2x .62 saito 4 strokes...with twin sync.....great sound.

but thecomanche with 2 twin engines....so intotal 4 cilinders :-)...... oh...what a sound.

Thanks...I thoughtbecause the seugull piper is a little bigger the engines would fit better....butthat is not the case....then I am going for my"top" commanche :-)

Thanks,


Kor
Old 08-10-2012, 04:30 AM
  #70  
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Default RE: Seagull Piper Twin Comanche

thats why I chose the .90 instead of the .60 twin....the .90 is more powerfull ( the .60 Twin is like a .40 two stroke), the .90 has almost the same dimensions and the weight is less then the .60.

ok....2 of those is a little heavy....but i can put glow battery's etc in the back of the fusulage to get the cg right.

but the sound.....ow man.......


kor
Old 08-10-2012, 04:38 AM
  #71  
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Default RE: Seagull Piper Twin Comanche

Looks the choice is

Retracts and single engines OR fixed gear and Twin engines ...

but i'm still a bit afraid about weight ... even with your TOPP fiberglass one []

Alain
Old 08-10-2012, 04:58 AM
  #72  
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Default RE: Seagull Piper Twin Comanche

Power enough Alain with those 2 twins....zo even the retracts can go up

The looks is so mutch better with retracts.......

I will try my comanche with 2 dummys of 720 gram (the weight of the .90 saito twin)....lets see what the cg does....and if I can correct it.

You wil hearmore later


Kor
Old 08-10-2012, 05:24 AM
  #73  
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Default RE: Seagull Piper Twin Comanche

Hi Alain,

it is not so bad after all....I have been looking for the weights of those enigines.

A saito .72 = 470 Gram the .62A who I have nowon my Twin Otter = 420 gram
the .90 twin = 720 gram

so (2 * 720) - (2 *470)= 500 gram......that is to overcome.....
when I use my own saito .62 than the differance woulde be (2*720)-(2*420)= 600 gram

a little playing with receiver, servos, batteries would do je job to get the cg on the right place

I let you know what I decide......but oh man.....2 of those twin 4 strokes exact in sync.....mindblowing


kor
Old 08-28-2012, 04:33 PM
  #74  
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Default RE: Seagull Piper Twin Comanche

Hi Fellahs,

When I first saw this model a while back, I thought it was just another foamie.....don’t know where/why I came up with this idea ??

Then I spotted it at Horizon Hobby and read all of the specs. Looks good.........all built up wood.



I find myself taking out my Seagul Dual Ace quite often. It’s one of my high-mileage twins. What a great, dependable flyer ! If this Seagul Comanche flies as good as my Seagul Dual Ace, I’ll be a happy camper !

I have a pair of broken-in OS .72 4-strokers but don’t know (yet) if they will fit.

I should be ordering my Comanche tomorrow.

Joe M.
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Old 08-29-2012, 03:05 AM
  #75  
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Default RE: Seagull Piper Twin Comanche

Hi, Joe

I have a pair of broken-in OS .72 4-strokers but don’t know (yet) if they will fit.
OS 72 just looks to be an over-bored .56 ... ( same stroke, also as the .62 !!! ).
Sooo ... no problem for them to get into cowls , nor weight problems ...

Alain

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