8178

My Feedback: (17)

On my postage scale my OS 25 FSR is very close to 8 oz plus 2 oz more for the muffler. I read on another thread that Webra changed the 36 liner to aluminum and the engine might be less weight than the 9.4 oz advertised.

summerwind

no, i am saying that kept light, this larger version will fly fine with an open exhaust ST .23 (only as a comparison). we both know that this is not possible though, so a more modern engine with just a muffler will fly this plane superbly. thing is, it just needs to be propped for pull, not speed. the FF +10 with an open exhaust (butterfly exhaust valve) and an 8x6 prop was vrey fast. with the light radios we all enjoy for this size plane, the added engine weight won't be a problem. a tuned pipe isn't needed unless you want a balistic pattern plane, and with the yaw effect that is inherent from the kwik fli, it'll be even worse at higher speed.
a Norvel or Webra would be the best bet, but an OS25 fsr is doable, and probably the only issue would be locating the battery behind the wing.

as much as i love Jett engines, they aren't for this sweet machine.

doxilia

My Feedback: (3)

Although I did mention them, I'd have to concur. A vintage classic like this ought to be flown with a simple and low cost light engine - not a speed monster. My preference would actually be the Norvel which is why I posted info on it. Super light and quite effective for its weight - so I'm told.

Very nice engine design too.

David.

summerwind

hehe.....realistically i would go with a Jett on anything though............it needed to be mentioned.
thing is, they are well suited to just about anything, but in this case it would probably end up bringing this plane down in pieces.....as in KaBoom!!

Texastbird

Ok, my vote is for a VECO 19 with a little port work with a mini pipe. I also saw these retracts the other day and they look like they might work on the smaller planes.
http://www.scaleflying.com/Electric-...pcs_p_365.html

8178

My Feedback: (17)

Looks like the Webra 36 is out! The vendor emailed me today indicating that although he told me on the phone that he had 36s available, it was not the case. Apparently the shipment he received has less 36s than he expected and there are no more.

So now I’m back on the OS 25 FSR plan. From what I can find on the net it is apparently rated at .8 HP which is very close to the latest OS 25s. I’m reviewing pipe options but will need a header that will position the pipe under the wing. Plan on side mounting the engine to clean up the nose and improve fuel draw.

To be continued….

doxilia

My Feedback: (3)

Mike,

the FSR sounds like a very nice match to the FF+10. The Macs 234x series of headers should do the trick on the FSR. I am expecting an SF in the mail (from South Africa!) which should use the same header. I can cross check the bolt dimensions against your FSR if that helps since the Macs site makes reference to the SF and later models. For pipe the 1020 is a sleek little unit.

Fifteen minutes ago I spotted two nice Webra auctions - one was for a Speed 28. Here are a couple of pics of it. It has a heli head but it is somewhat vintage looking being round and all. I don't believe there were any differences between the Aero and Heli Webra's other than the heads. It is an ABC engine with TN carb. I mention it because it is still possible to find these gems from time to time as I'm sure you know.

You can plan on the FSR and then if a Webra comes along, you can just swap out the engine mount and drill some new holes for the 36 in a new mount - everything else should be usable (header & pipe). Also, other than the 36 you can also look out for a 32 or a 28. If I come across something, I'll let you know.

I suspect you are probably already ahead on this though.

let's have a CU look at those Midwest plans!

David.

R_G

My Feedback: (1)

I had one of those Webra .28 heli engines on a GMP Cricket years ago and It was one of the best engines I ever had! Too bad Webra went out of business! They made a great product! []

RG

8178

My Feedback: (17)

Looks like I might have found a Webra 32 from the same place that thought they had a 36. We will see, could take a couple of weeks before it is here.

Got my Tower order in for all the stuff I need to build the kit including some Futaba S3115 micro servos, Orange MonoKote, etc. Also found the spinner I wanted from another source.

To be continued….

doxilia

My Feedback: (3)

Those are some nice little servos. I need to get a few more myself.

The 32 is going to make that FF+10 move out in a serious way - probably blow your Speeda right out of the water...!

Ralph,

glad to hear the news on the Webra 28!

David.

summerwind

i may try them too.......i usually use 6v packs for flight systems, but i can shave another little bit of weight with a 4.8 pack.
or, i wonder if there is a way to safely regulate the power down to 4.8 from the Rx?

AllTheGoodNamesAreTaken

My Feedback: (180)

Mike,
You could run a 2 cell lipo and regulate it with one of these:

http://www.smart-fly.com/Products/Regulator/4.htm

8178

My Feedback: (17)

Talked to Spring Air today and requested their drawing for the mini retracts. Apparently they are very busy filling orders and that is a wonderful thing for them. Got to love it when American manufacturers have lots of work!

Should have the drawings later today so I can see if it will be possible to install retracts in this little beast. I’m most concerned about how I’m going to get the nose gear to fit in the space under the fuel tank. The battery will be going behind the servos to help balance out the Webra.

To be continued….

AllTheGoodNamesAreTaken

My Feedback: (180)

The Webra .32 is 8.8oz sans muffler.

8178

My Feedback: (17)

Yes, only about .8 oz more than the OS 25.

doxilia

My Feedback: (3)

Mike (summerwind),

I was going to suggest what Jeff just did. But I have also operated the S3115 with 6.6V nominal off 2S LiFe batteries (I used A123's) - regulated to 6V ($10 regulator). Probably not a good idea in the long run but the servo didn't burn out.

There are also these:

http://www3.towerhobbies.com/cgi-bin...?&I=LXYAS7&P=7

which come in at 3 oz - probably a tad heavy for the FF. Plus there would be the regulator weight and cost. It is probably a better plan to just use four 500-800 mAh NiMH cells.

David.

doxilia

My Feedback: (3)

Mike,

so what battery will go behind the servos?

Something like this?

http://www3.towerhobbies.com/cgi-bin...?&I=LXPYL6&P=7

http://www3.towerhobbies.com/cgi-bin...?&I=LXFRT9&P=7

Or even like this?

http://www3.towerhobbies.com/cgi-bin...?&I=LXHBB0&P=7

The first two come to 2 oz while the last to 1.3 oz.

David.

AllTheGoodNamesAreTaken

My Feedback: (180)

That little 2/3AAA pack is a good idea. I've used them on .25 size AT-6 Texan pylon racers with good results. It's a good idea to keep an eye on the battery level though as 350mAh isn't that much.
If you already have a lipo charger, this battery and regulator would weigh less than 2oz and give 900mAh of capacity AND you the ability to fast charge at the field if you find your self burning lots of fuel...

http://www.all-battery.com/74volt-90...orbladecx.aspx

8178

My Feedback: (17)

Thanks for all the ideas. I’m kind of a NiCad guy! Been using them since 1966 and they have never let me down. Expect I’ll keep on until they are no longer available.

8178

My Feedback: (17)

Yippee!!!

To be continued….

8178

My Feedback: (17)

Looks like the servos should fit nicely! In the image below the Futaba S3115 micro servo is lined up with the back of the Kraft servo shown on the drawing.

To be continued….

8178

My Feedback: (17)

I’m not sure which Karft servos are shown on the plans. They look a tad bit smaller than the KPS-12s that are 1.2 oz total weight. The S3115s are .6 oz so I should save about 2 ozs with the mini servos. Kind of funny that the KPS-12 only had 18oz of toque and we thought that was adequate back in the day. The S3115 has 38.9oz, but sadly they are made in China!

To be continued….

8178

My Feedback: (17)

Received the scale drawings for the Spring Air 600 Series retracts today and I resized them so I could print them full size. I attached the sized drawing. I cut out the retracts from the drawings and overlaid them on the plans. They look like they should fit. Apparently a complete two gear system is 4 oz less struts so add something less than 2 more ounces for three units.

To be continued….

AllTheGoodNamesAreTaken

My Feedback: (180)

Looks like the nose wheel is going to hang below the bottom of the fuse when retracted. Too bad they don't make rotating nose wheel retracts...

doxilia

My Feedback: (3)

Something that can be done to tuck the wheel in is to bend the last section of the strut backward when extended giving a sort of scale like look to the strut/axle/wheel assembly. When retracted, the main length of the strut is lower down in the fuse but the position of the axle is higher. I see a 1-1/2", 1-3/4" max wheel here.

Something that might complicate matters a bit is the need to move the firewall back due to the longer engines (OS or Webra). The nose wheel would end up tucked in somewhere mid draft in the fuse into a wing LE notch. My concern would mostly be the fuel tank since an OS 25 or Webra 32 will be happier with a 5 oz (or even 6 oz) fuel tank.

But if there's a will, there's a way. I'm sure Mike will figure something out.

David.

P.S. By altering the fuse side planform slightly without changing design moments, here's how I solved this problem on another 25 sized design. One can think of the FF+10 as similar to this, with a curved bottom and the top cut off just above the tank. Of course, this is a RE inverted engine design so it is perhaps not that relevant. But, by growing the fuse height slightly, the same concept might apply. It could be as simple as using a thicker piece of wood for the fuse bottom forward of the wing LE.