The perfect plane for the DA 85

[sensei]

Just today; I purchased a new H9 35% 260, and a DA 85 for power; when everything gets here next week I am going to strip the covering and put the airframe on a very strict diet. The target goal is 22lbs. I think it will have ballistic power, and very good 3D and IMAC performance with or without a tuned pipe. I guess time will tell...

Bob

[Craven]

	Quote: Originally Posted by sensei
	Just today; I purchased a new H9 35% 260, and a DA 85 for power; when everything gets here next week I am going to strip the covering and put the airframe on a very strict diet. The target goal is 22lbs. I think it will have balistic power, and very good 3D and IMAC performance with or without a tuned pipe. I guess time will tell... Bob

Please do a diet thread on this for us Bob!!! I, for one, would love to see your work getting this down to 22 lbs. Thanks

[sensei]

OK, I will

Bob

[dbcaster]

I had a DR Extra at 23 lbs. with the 85 and a pitts. It was a rocket and blast to fly, 22 lbs. will really be sweet

[gareth.ky]

I say put it on the QQ 101 with a pipe.

I built a Carden 35% 260 around an 85 on a KS-95. The airplane is in the neighborhood of 25 1/2 pounds. The motor has enough power to haul it around and pull out. Not foamy insane power but more than enough for general hucking around.

After going to regionals and seeing the same airframe at 29 pounds with a DA 100 fly its pretty clear that I need more power. If your doing an upline on a windy day and then continuing into a figure 9 its pretty apparent. Most people just hucking around wont care about this though, its really specific to IMAC. There is no way I can shoe horn a pipe into the 260 so I will have to switch to a 100 for more power. For IMAC flying some added mass is not a bad thing.

I had nothing but trouble with the canister and everyone I know personally that has run the KS-95 on the 85 jug (including the 170) has switched over to stock mufflers. New canisters, tuned pipes and possibly headers are on the way for the 85 and 170 to let them breath. So next year that shouldn't be a problem.

I have been running mine on the slimline muffler and it has shaken two apart so far. Its been back to DA and its not the motor. I talked with Slimline and they say they have been through 3 designs so far, the stacks keep falling out. they have a new design that should fix this issue and they have offered to replace both of my mufflers.

QQ designed the 101 around this motor, its got a pipe tunnel built right in. You wont have to worry about breaking mufflers with a tuned pipe. You don't even have to run a spinner. I think that setup would be very reliable and fun to fly.

If I wasn't trying to buy a trailer this winter I would be putting my 85 in one next spring.

[bodywerks]

	Quote: Originally Posted by sensei
	Just today; I purchased a new H9 35% 260, and a DA 85 for power; when everything gets here next week I am going to strip the covering and put the airframe on a very strict diet. The target goal is 22lbs. I think it will have ballistic power, and very good 3D and IMAC performance with or without a tuned pipe. I guess time will tell... Bob

Unless you don't like the scheme, I wouldn't bother with tearing the covering off. Even for you, there aren't too many places to shave weight off the structure of this airframe. The control surface sheeting is not solid so you can't put any lightening holes in them, the fuse is already borderline weak and already twists pretty easily, and the wings are among the lightest you will ever find.
I couldn't get but an ounce out of the hatch assembly, as they beat me to all the lightening holes except fot the cockpit deck.
Even the engine box is lightened about as much as you would want. I did manage to drop a couple ounces there by drilling a big hole in the firewall, though, and a few holes in the sides.
The standoffs will have to be ditched if you are using an 85, and I know a few ways to save a couple ouces there using a balsa spacer and titanium bolts, but you will probably need the noseweight.
All you really need to do with this plane is upgrade to carbon on the wing tube and main gear and use a lightweight battery system and you will hit the 22 pound mark easily.

[BigBird]

Bob,
I got to agree with Body werks on this one. You can get to your target without recovering this bird. Of course that takes most of the fun out of it for you! And it would be easier to lighten with a bare airframe. With just using the lightest equipment selection the H-9 Extra 260 comes in light.
It is not like cutting out the lumber yard in an SD!
Jason

[sensei]

Thanks guys but as you said Jason; that would take all the fun out of it, and it would be much easier to perfom all the mods I want to do with it undressed. maybe I should shoot for 20 or 21 lbs. LOL

I spent the weekend flying with George Hicks in Savannah and got to fly his H9 260, the airplane really flew well; even at 29 lbs, and that is what inspired me to do this...

Bob

[Craven]

I can't wait for your lightening thread on this Bob!

[gareth.ky]

That was the other thing with the 85. Even on mufflers I was running 8oz of nose weight to get the CG to where Carden specs it. That 8oz could be doing something useful like, pulling the airplane.

[sensei]

I won't be adding any weight to the nose of this airplane, I will pull enough weight out of the tail; come hell or high water to compensate for the lighter engine weight.

Bob

[BigBird]

Bob,
McConville has one with an 85. Must not be that much of a problem.
JD

[~SnApRoLl]

You guys might think I'm crazy or just plain nuts! But I have a DA-85 that's going on my 2.3m Comp-Arf Extra 330L.

Shawn

[Surly_Schmidt]

Diverting mufflers are not always an option, so comparing a piped 85 to a muffled 100 is only appropriate where noise is of no concern. If you got to add pipes of some sort to the 100, the difference will be quickly at pounds rather than ounces.



For an all out diet 85 wins, substantial weight savings are made up of many small ones.

[dbcaster]

Agreed, however I don't think the piped 85 is much quieter than a 100 on stock mufflers. I never took a Db reading but the noise seemed about the same.