HighPlains

My Feedback: (1)

This a strange thread for me. I worked for a period at FMC on a special version of the Bradley about a decade later. My last project was to be a version of the 7.62 weapon system for use on "soft targets". But I went into commercial electronics soon after. Afterward I told anyone that asked that I was at FMC to do horns, wipers and turn signals.

378

My Feedback: (4)

You could either A: Build it out of foam or B: Run the lift bag off of a brushless motor powered off the receiver pack.

1QwkSport2.5r

I thought I could probably use a small fan motor and separate battery connected to the 3rd channel on my radio for backup air power. I think a small CPU fan running on 24v would do the trick. All it would need to do is keep it afloat until I could cast a fishing line over it. A rubber one-way reed valve under the fans would keep the inlet closed when the back is inflated under the engine and only open if the electric fans were kicked on.

I got other projects to deal with, so this is a summer project for next year if I get my plane built this winter.

378

My Feedback: (4)

Computer fans don't like 24V. Trust me on that one, seen plenty a guy build a crazy gaming PC, overvolt his fans, and smoke them within just hours. Besides, you can get some that will pull 200CFM on 12V, although they'll sound like an EDF the whole time.

1QwkSport2.5r

They make 24v small fans. I think they use 10-15 watts or something.. Radio Shack used to sell little fans for 12v or 24v. I wonder if they still carry them....

rcdude7

My Feedback: (264)

I happen to have 65 sportster that has a "91" on the backplate and it came with a bag of 12" unmarked rev-up props, I never suspected it might be a drone engine. I have not run the engine, but it looks to be a earlier K&B without the bronze bushed crankcase. I suppose this crankcas will wear its shaft bore quickly? i don't yet know what I will do with this engine but I might put it on the stand and run it some. I have some fox fuel w/20% castor oil lube.

1QwkSport2.5r

That engine has drone written all over it. If you plan to use it in a plane, get a different carb for it. The midrange is obnoxiously rich. Fine at WOT though.

The crankcase is really high in silicon. With the proper oil and content, it should last a long time. I have 2-3 gallons through mine and there is a little play but not much. I would up the oil to 25%. Mine ran better on it. Mine won't idle for beans now though. Idle mixture is too rich in the "lean" position.

earlwb

I was curious, without trying to start and run a K&B .65 Sportster engine, how can you tell if it is a Government Drone special or not?

I have seen some engines without a number on the left mounting lug and some engines with a number stamped into the left mounting lug.
But some numbers start with a J, some with a G and I think that there were some start with a R on them too. But more than one engine may have the same number on it too. So it apparently is not a serial number then. For example G29065.

1QwkSport2.5r

The target drone engines don't have serial numbers stamped anywhere. Most of them have a raised impression of ":91" on the backplate.

I met a guy who has a drone sportster .65 and swapped carbs on my engine. It throttled normally. The other engine I borrowed the carb from was a drone engine as well. After trying a few things, I think the hole in the brass tube inside the barrel is too big.

With the other carb, it throttled like a dream. It also idled at 2200rpm for 20+seconds with a 13x6 APC.

earlwb

It had me wondering. I have a .65 Sportster engine that I bought off a guy around 20 years ago and it worked fine, no serial numbers or engine numbers on it. Then more recently I got another .65 Sportster engine and it had a G29065 on the left mounting lug. I haven't run the engine but from its appearance, I can say that someone used it for a while OK. It even came with two mufflers a Pitts and the OEM one. But then I noticed a couple of old  Ebay auctions where someone was selling a .65 Sportster engine with the same number on the mounting lug on the engines too. None of the engines have a "91" on the backplate though. So it was just something that got me curious.  So then the numbers on the side of the mounting lug probably mean something to the K&B factory though.
Thanks

1QwkSport2.5r

I would guess the G29065 to be a more modern serial number. Does that engine have a bronze crank bushing up front? I don't know what the number would mean, but neither of my engines have any numbers.

I think there was another backplate stamping that meant it was a drone also, but I cant recall off hand what it was. I think its on the mecoa forum. Chances are, Earl, neither of your sportsters are drone engines.

This guy I know has two of the foam Mig 27 airplanes that are not built yet and 1 K&B Sportster .65 thats pretty well broke in. We didnt run his engine, but we ran my engine with his carb. Totally new animal. Same backplate stamping as my two. Though I never tried my other sportster carb on my running engine. I only swapped idle disks. This kinda makes me wonder now...

I was really floored with the 2200rpm idle I got (on the good carb). Excellent midrange - it throttled up perfectly even after 10 seconds. It never ran that good for me. I might be able to get one of the M27 drones and learn to fly on that gigantic thing instead of building a kit.. It only has ailerons and elevator, so I'll add a Rudder to the tail.

1QwkSport2.5r

Finally got the plane the engines go to... Missing two compartment hatches in the aft part of the fuse, and one of the ailerons.. otherwise its complete. Hopefully should have it built to fly by the summer's end..

(I know its not totally on-subject.. sorry.)

flyingagin

The missing parts will be easy for you to fab.
It's a plane with a sportster in, cool.
What are you going to paint it with?
Do you use nitro in your fuel or is it just methonal and oil?

1QwkSport2.5r

This plane originally came with a Sportster 65. I am going to paint it but I don't know what scheme yet. I'm going to coat over the paint with waterbased polyurethane to protect the paint from the oil and fuel. I use low nitro fuel in the sportsters. 5% nitro 20% castor with a hot glow plug. I need to order a Perry carb for the engine and maybe make a mousse can pipe for it. Need to find out what solder stick to aluminum.

I may put my ST 90 on it at some point as well. Probably will use a 13x5 or 13x6 APC prop. Nose gear, tail dragger is the plan right now.

flyingagin

1QwkSport2.5rtry here
http://www.harborfreight.com/pack-of...ods-44810.html

Ken

earlwb

It is looking good.
It sure would be nice if whoever used to make the foam plane parts could make a bunch more.
I think it would sell well. No frills just the foam parts.

spaceworm

At a recent swap meet a seller was offering the foam kit for $20.00. He also had the .65 engine for $30. I don't know if he had more than one kit, but I may be able to source his name and contact info. if desired.

1QwkSport2.5r

Put a good civilian carb on my drone sportster and flogged it today.

90*F air temp, humidity 60%+, 5% nitro 25% castor, MC59 plug.

Master Airscrew K-series props:
11x6 - 13,320rpm / 2330rpm idle
11x7 - 12,870 / 2370
12x6 - 10,890 / 1890
12x8 - 10,830 / 1700
13x5 - 11,040 / 1590

APC 13x6 - 10,860 / 1850 idle

My numbers are down a little, but I raised the oil content and mother nature raised the air temp and humidity on me. The engine throttled very well and seemed to not like being set 400rpm rich of peak, top end of the midrange would be a little blubbery but recovered 10 fold better than the original drone carb.

Next time I run it I'll try it without muffler pressure and maybe a different muffler.

buzzallnight

This has been a very interesting and informative thread.
Just wanted to say I have two bare bones Carl Goldberg MIG 27s
available cheap for pick up in MN
but shipping costs too much.

earlwb

Man I wish I could figure out a way to get up there to Minn so I could take those two planes off your hands.
But that is a  long drive from way down here in Texas.
It gets harder as I get older and older  too.
But if you are willing I think I could come up on one of the holiday days such as the Labor Day weekend, I could leave Friday  or something.
But then it depends on what you are doing too.

1QwkSport2.5r

It's too bad these planes are so big. I wouldnt mind a second one, if nothing else for parts. Are there any spare parts or just 2 complete planes?

I haven't decided how I'm going to paint mine yet. I definitely have a couple K&B logos in mind.

spaceworm

Anyone compared the flights of the Mig powered with the plain bearing HB .61 to the K&B .65? I think the HB was fitted to some of the target drones? I have an HB .61 (with BB) and both a K&B .61 and a K&b .65. I have flown them all but not done any comparisons. Thanks.

earlwb

Buzzallnight still has his planes. I don't think I could make the trip and drive all the way up there and back.
I'll have to pass, just too far to go for me.
Thanks anyway, I appreciate it a lot.

earlwb

Considering that they flew the jets around at 1/2 to 3/4 throttle, RPMs and speeds the weaker HB .61 would not have been a problem on the models. But the K&B .65 has the performance edge, being it is Schuerle ported whereas the HB .61 is crossflow scavenged (a baffle on the piston). Now the HB .61 PDP engines would probably have a slight edge over the K&B .65 though as the ball bearings would let the HB engine rev up a little higher. But the .65 engine tends to like larger props though, and those could be out of the power band for the HB engines. But the props they used on the jet models would work for both engines.

1QwkSport2.5r

I got my hands on some "civilian" Carburetors for my Sportsters and went on a prop testing spree.

74*F/64% humidity, 5%nitro 25% castor, McCoy MC59 plug, APC Props, factory sportster muffler.

11x8 11,700/2,400
11x9 11,600/2,280
12x6 11,550/2,300 (12,000 open exhaust)
12x7 11,100/2,100
13x6 11,100/1,950
13x7 10,600/1,950
13x8 9,900/1,800