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Twin Aero Commander 685? Anyone?

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Old 08-12-2006, 05:21 PM
  #1
jetfixr
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Default Twin Aero Commander 685? Anyone?

I have always loved the twin commander line of aircraft. My father has flown a Turbo Commander 1000 for the last 25 years, and I has taken me for rides multiple times which has led me to this. I started looking for a good looking model of a twin commander a while back, but could not find one that I liked. I like the streached models, and especially the Turbos. Having not found one, I decided to look at about a million pictures, and draw my own plans and scratch build one. I figured I would have a better luck building the piston model naceles than the turbos, so I built a 685 which is basically a 690 with piston engines. I have the model mostly built, and would just like some feedback on it. I will upload some pics soon, as I don't have any right now. I have the airframe built, and fuselage covered. It has a wingspan of about 76 inches I think, and a length of about 66 inches. I have kind of lost motivation on it, so I was hoping you guys could help me out with that. I have twin 46's for power, but am still thinking about it.
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Old 08-13-2006, 01:19 AM
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Default RE: Twin Aero Commander 685? Anyone?

I do have some pics of how it looked a while ago, but no current ones. The first four were taken the same day, but the last one of the landing gear was a while later after I changed it to a strut instead of a wire gear. The gear is still too long, and will need to be shortened. Since these pics, I have finished all the windows, and put a simple stripe scheme on the fuselage of blue and silver. This is my first attempt at scratch building, and I wanted to keep it simple. I still have a lot of work to do on the wing. It also has working anti-collision lights, and position lights. I will try and put it together tomorrow and take some current pictures of it. Just ignore the guy in the fourth picture.
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Old 08-13-2006, 03:19 PM
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Default RE: Twin Aero Commander 685? Anyone?

Congratulations on taking on this project and just 'making it happen'. I applaud anyone willing to take the time and effort to build from scratch.
I have some wrench time on the Turbo Commanders, so I await your progess pictures. I think the wing span sounds about right for the .46's.
Hopefully you've been reading about how to fly and tune twins.

Jim
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Old 08-14-2006, 04:05 PM
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Default RE: Twin Aero Commander 685? Anyone?

Well, I put it together and took some up to date pictures of it today, and I think it looks ok, however you guys are the real critics. I also measured it, and the actual dimensions are 74"wingspan, and 68"fuselage.
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Old 09-05-2006, 12:02 PM
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Default RE: Twin Aero Commander 685? Anyone?

Very nice. The Aero Commander´s are among the greatest looking twins ever built in my opinion. I think the winglets on your model adds a nice touch to the plane.
I completed a 1/5-scale 500S Commander from Palmer Plans in 2003. Powered by a pair of OS 91 four strokes, it has proved to be an easy to fly airplane, showing no bad habits whatsoever.
During construction I had some trouble bringing the CG enough forward. I ended up with most of the radio gear, (including Nicad´s for the on board glow system) in the nose of the model. I am flying my plane with the CG at 25% MAC.
I have been told that the high degree of taper in the Commander wing, requires a high amount of washout. According to Dan Palmer, the full scale Commander uses no less than 6,5% total of washout in the wing. This amount is also incorporated in the model. (+3 deg. at wing root, - 3,5 deg. at wing tip)
Good luck on your project.

/Leo

BTW, I made an electric conversion of the plane last year. Now I´m thinking of going back to IC power, as I´m missing the sound (and smell) of the four strokes
Video of the electric maiden flight here: (12 Meg, poor quality, sorry)
http://www.youtube.com/watch?v=00oKuXjfxZI


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Old 09-05-2006, 08:35 PM
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Default RE: Twin Aero Commander 685? Anyone?

Leo,

Yes, I have seen your electric model on youtube! I thought it looked and flew great. I saw that video while I was browsing one day, and that is partly what inspired me to get mine back out and work on it some more. I did build in some washout in the wings, because I have read about the problems with some of the production models. I haven't gotten all of my gear installed yet, but I have had to put some weight in the nose just to keep it from falling back on the tail when I have it put together, so hopefully I can get it balanced out pretty good.

Jeff
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Old 10-11-2006, 03:25 PM
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Default RE: Twin Aero Commander 685? Anyone?

Hi everybody, i'm a newbie to the forum.
For all interested. I have a Shrike (Aero) commander, 84!QUOT! span fitted with 2 OS 46's. it was built by a friend about 30 years ago but never finished or flown. He built it from some plans he scaled up from Control Line plane plans. I acquired it and got it into a flyable state. (It fly's like a dream) It's like a big twin trainer. And has this fantastic turbo-prop whistle when i do a slow low pass. i have posted a short video on the RCU video site. Unfortunately there was a heli buzzing in the background during videoing, masking some of the great sound which only a twin makes. Hope you all enjoy it. and good luck to all you Aero Commander modelers
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Old 10-11-2006, 06:08 PM
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Default RE: Twin Aero Commander 685? Anyone?

Man, that looks great. I got my ATP in a 690 commander. I just bought a kit of the commander. Look forward to it arriving. Its a cool plane.

Congrats, that looks very nice
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Old 10-12-2006, 04:04 AM
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Default RE: Twin Aero Commander 685? Anyone?

Hi. Thanks for the encouragement I will fly-it till the wing come off.
Just for interest[quote] I put my Pocket PC in the plane a few weeks back working the GPS so i could log the Altitude, speed etc.
Got a shock and so did my fellow modelers.
Just normal sort of regular flight max hight she was at was 540 feet A.S.L and max cruising speed on half/three-quarter throttle was 85 mph. and i about a 6/7 minute flight she covered 6.5 miles.
It's amazing what we guess the plane is doing and what is really happening.
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Old 10-12-2006, 01:29 PM
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Default RE: Twin Aero Commander 685? Anyone?

great looking so far.

I hope you get a visit from the Good Cowl Fairy, and dont have to go crazy getting some engine covers for it.
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Old 10-19-2006, 04:21 PM
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Default RE: Twin Aero Commander 685? Anyone?

This is very similar in size to the old Bridi Aero Commander. You might want to do an RCU search on it.

One thing to watch out for. TIP STALLS. This is a high taper wing, which is very tricky at this scale. I remember seeing plans for the full scale plane, and it has 7-8 degrees of washout in the tips. You should have at least that much. If not, float your ailerons up and flaps down for takeoff and landing. At least until you feel out the behavour of the plane.

I would hate to see you scratch such a nice design and have it pinwheel in at the end of the runway.
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Old 10-19-2006, 04:23 PM
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Default RE: Twin Aero Commander 685? Anyone?


oopps, Yeah I see Leo's already covered the tip stall thing. Two votes for washout.
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Old 10-31-2006, 10:15 AM
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Default RE: Twin Aero Commander 685? Anyone?

One thing that has not been discussed is thrust lines on the engines. I am working on a Modair Aerocommander with 50cc motors. I have heard to use at least 4 degrees of outward thrust and up to 7 degrees. Does this seem reasonable to you guys? This is my first twin.
Paul
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Old 11-01-2006, 01:53 AM
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Default RE: Twin Aero Commander 685? Anyone?

Hi! My Commander has the engines set straight ahead and fly's very well "as you can see from the RCU videos.com pages". I have read a number of articles and most of the experts advise to have the engines straight ahead, i once bought a mosquito built by someone else which had the engines looking out, it did not fly well and the usual happened Ooop's.
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Old 11-01-2006, 04:30 AM
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Default RE: Twin Aero Commander 685? Anyone?

My Palmer Commander is designed with the left engine straight ahead and 2 deg. of right thrust on right engine. I cannot say if this setup is optimal, as I have no single engine experience with the plane.
More powerful engines could make the setup more critical I guess

Nice scale flying on your video pshel176!
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Old 11-01-2006, 06:36 AM
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Default RE: Twin Aero Commander 685? Anyone?

This seems rather odd. I think this is a manufacturing error as i can't see any reason for this. I know somw people use outward thrust for lost engine purposes, the idea being that an engine point out on the running engine side is supposed to help with keeping the plane from turning towards the dead engine. but if one is straight and the other at an angle it it would only work if the appropriate engine went down.
The only other explaination is rotational thrust of the engines would mean a port engine out situation means the weight of the plane is hanging on the starboard engine and increasing the rotational thrust, where as a starboard out situation means the weight in opposing the rotational thrust of the port engine so no ofset is needed. Think about single engined planes, we put side thrust on to counteract the rotational thrust. if we moved the engine first one side then the other the weight of the plane hanging one side or the other would either increase or decrease the rotational torque of the engine.
This is my thoughts on the matter, i hope it helps you, I've no doubt someone will come up with other ideas and explanations, persanally i would keep both engines straight ahead. Unless you can find someone who has the experiance or knowlege to inform you better.
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Old 02-14-2007, 08:10 PM
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Default RE: Twin Aero Commander 685? Anyone?

I'm a newbie on rcu, had to get in on the Commander subject. Best looking twin out there I think. I have an old Shrike drawn by J Birdi, 79.5 ws, 715.5 wa, 56.5 fuse, 12.25 lbs. It was drawn for twin .40's but I used a pair of .60's I already had. My boss owens a full scale 560 not in the air yet.
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Old 03-27-2007, 08:56 PM
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Default RE: Twin Aero Commander 685? Anyone?

Hello here is mine aero comander Shrike from great planes, 18 yers olde now want to use 2 os70 4stroke? or is it to overpower
mvh olav
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Old 03-31-2007, 12:54 AM
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Default RE: Twin Aero Commander 685? Anyone?

Hi there! you've got a great looking plane there. nice fitted retracts. the engines size will depend on the wing area and all-up weight, also another factor will be the room in the cowls as to weather you can fit 70 FS's.
I like the looks of it. Don't know what kit it's from, I'm Green. "wished it was mine" Can you find another! I want one... Good Look.....
best wishes paul.
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Old 03-31-2007, 07:03 AM
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Default RE: Twin Aero Commander 685? Anyone?

Hello, thanks yes it 18 years old now, is a modell from great planes, the boddy on my plane ready to paint nov,gona juse
proffesonal to do this,her som more pics

Ps. Here is the plane i gona paint from i think [8D]
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Old 04-01-2007, 01:25 AM
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Default RE: Twin Aero Commander 685? Anyone?

Excellent "I like it". From the Photo it looks like you control the throtals from a central servo with bowden cables. "Don't Do It". Mine came like this the cables were sticky and i had difficulty balancing the engines RPM. I cut off the cables and fitted 2 micro servo's in the engine bay's. I can now set the engines from the transmitter. And also I can link them to the rudder so the engines help to steer the plane and give better ground control.
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Old 04-01-2007, 09:06 AM
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Default RE: Twin Aero Commander 685? Anyone?

hello and tanks i gone use 2 micro to in front off engine bay's.

1 flaps
1 rudder
1 elvator
2 ailron
2 trottel
2 gear
1 ligte mix to gear
[8D]
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Old 04-03-2007, 01:01 PM
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Default RE: Twin Aero Commander 685? Anyone?

[8D]Hello more pics,gone take it to paint shop soon,getting scale legs and bulding copit to
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Old 08-30-2011, 11:28 AM
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Default RE: Twin Aero Commander 685? Anyone?

I have a 30 yr old unbuilt Bridi kit with Robart retracts and spinners that i am not proficient enough to fly. Will sell for $500 + shipping.
It has a once piece fiberglass fuselage and ply covered foam wings.

Rafeek
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