dphill2

My Feedback: (1)

Ralph,
Lil Dave is going to use a OS 61 RF Rear Ex with pump . He is going to mount the engine side ways and run the header & pipe straight down the side of the fuselage. With that being said I know it will take 16 oz to fly Expert pattern and have room to land with the motor running. We are very interested to find out if the tank will fit as Lil Dave had to return his because of some damage to the fuselage...
We did not have time to check out the tank !!!!

Dave...

airraptor

My Feedback: (66)

Ifinny someone wanted to use the 65 AX with a 11x7 and a full pipe. I was sayingthat engine wouldnt respond well to that set up.

Yes the 65 i have i ran with out the Baffle on the 11x8 APC. I now have the 65 to run 11,700 on the APC 12x10 with a Jett muffler.

TonyF

My Feedback: (92)

Matt, thanks for the comments. I have no doubt that someone can post a bad experience they had with Horizon. It was just that I have always had good experiences with Tower that today I was a bit surprised.

One thing I have to say, be a little careful if you're going to use an E-Flite retract for the nose. They don't hold up to the kind of vibration that a screaming engine will give them. I had some problems with my nose retract in my P-7 and have since converted to Dave Browns on everything. I have heard if you shock mount them on grommets they will hold up better but I have not tried that. If I did this Dirty Birdy I would go with mechanicals myself.

ChiefK

David,

The ~12oz tank from WM is exactly the same shape as the one included with the DB. the WM tank is about 1/8" wider and maybe 3/4" longer than the DB tank. I sanded about 1/16" off the insides of the forward former and the wm tank slid right in.

The Webra is 3 3/4" from backplate to front of drive washer, and the engine mount provided is 1/2". So we've got 4.25" or so plus a bit more for engine clearance.
The cowl is about 4.5 inches (not counting the 1/4" overlap area). So bottom line.... no problem. That extra 1/4" of cowl length should be insignificant.

Thanks for making me measure....

Greg

doxilia

My Feedback: (3)

Dave & Ralph,

with a pumped engine like the RF-P (or SF-P) I'd imagine you guys could put your 16 oz tanks on the CG in front of the radio tray. This, assuming that the fuse draft is high enough at that location. A Hayes slimline (or other low depth tank) might help on that front. The battery would then likely have to go in the nose on a simple tray (or bundled in foam).

If anyone has started (other than Rusty), pictures would cut down on the speculation somewhat (at least mine)...

David

dphill2

My Feedback: (1)

Well Thanks for the info Greg !
I'm sure that Webra Speed will do the job, (I have about 10 of those motors and have never had any problems with them). I do think that the Webra is a little better on Fuel than the pumped OS. and I tried to get my son to use one because of the size and the fuel.
After what you said I don't think we will have any trouble with the OS....

Dave

doxilia

My Feedback: (3)

Greg,

nothing quite like a little prompting... Glad you measured. I know the European engines are long and although I haven't pulled out my Speed 61 in years, I have a pretty good feeling for its size.

As you say, there's not enough room in that cowl to contemplate cutting it back unless one uses a very short engine and/or has a way to mount it closer to the FW yet than 1/2"+ off. I was wondering about a backplate mount but those tend to use soft mounting anyway and would likley result in a longer length yet.

I guess GP made the cowl that length for good reason. I know I had to stretch the DB40 cowl length if i wanted to get a Rossi or any other European engine in there. It was conceived at first with a short non BB K&B 40 a good 1/4" shorter than most modern 40's and 45's. The same sort of thing applies with the 60's.

David

ChiefK

David,

The space between the servo tray and the forward fuselage area is 3.5" wide at the point closest to the wing opening, its plenty deep, but it narrows quickly with the fuselage rounding and then, of course, the really narrow area of the canopy (a receiver could be housed in that canopy area). Photo coming...

Greg

doxilia

My Feedback: (3)

So would a 16 oz tank fit?

ChiefK

I don't think a 16oz tank will fit there, but I don't have one to trial fit.

Greg

MTK

Greg,

Just saw the snap of the servo tray. No reason to have the throttle servo lengthwise. With minor surgery, you can turn the servo 90 degrees buying you another 3/4" clearance.

My 16 oz square tanks measure about 2 1/2" on side x roughly 6" long. Are you interested in a photo? It looks like that tank might fit.

doxilia

My Feedback: (3)

Wow! That tray is way in the front isn't it? Is there space to move it back in the aft portion of the wing saddle area? I guess by prying off some epoxy and lite-ply formers... not good.

A 16 oz Hayes Slimline is: 6-1/4"L x 2-3/4"W x 2-1/8"H

A 16 oz Sullivan Round is: 5-1/2"L x 3"D

It looks like the "feeder" tank approach might be the best way to get a full fuel load into the model. An 8 oz tank should fit without too much trouble in that area forward of the tray.

David

doxilia

My Feedback: (3)

Good point Matt. In fact, wouldn't one be able to position all three servos in the rear slot with perhaps a little offset if needed to clear pushrods?

However, one thing to keep in mind is the retract servo. If using pneumatics, it has to go somewhere. Maybe it can go behind the tray. And of course, if using mechanicals it gets even a bit more complex if one dispenses with the front servo tray area.

Mmm... I'd be inclined to saw off that servo tray and put it further back if possible...

David

KLXMASTER14

What? You may be sincere my friend, but you are sincerely wrong. The below pics are my O.S. .65AX turning 14,900 most certainly with a pipe. (15% Cool Power, 11/7 APC, Mac's Quiet Pipe/Ex long header).

And yes, I have flight time on it. Not only does the engine respond very nicely to the pipe, but has a great mid range performance as well. I can throttle back to 3/4 for cruise and it does not drop off of the pipe. Mucho power AND a nice powerband. What else can you ask for?

BTW, since breaking in, the same setup now peaks at 15,100RPM. It just keeps getting better.

-Robert

ChiefK

I saw that Dave. I've never put a 16oz tank in an airplane this size. Wasn't even thinking of doing that. My goal was 12oz and at 10.8, I'm close enough.

Greg

ChiefK

Looks like it could be moved back about one inch before it would get difficult to get to the servo screws.

Greg

doxilia

My Feedback: (3)

Well, it's true, the DB is one sleek and skinny bird...

In the DB I'm building the tray will go all the way in the rear. As I'm using a pumped engine I expect to position the tank half across the wing LE former. But then, I'm not building the ARF so I better keep quiet and get back to building!

David

Ralph White

I was able to get a 16 oz Fuji water bottle in the DB and have room left for receiver and batteries. I'll send a picture tonight. I am at band practice right now (Ache'n Back Old Time String Band). I ordered the Hayes 16 oz tank just in case it fits better than the Fuji water bottle.

Dave. sounds like your setup in the DB will be exactly the same as ours. I'm using the E-flite retracts. Hope what Tony F. said about them is not going to be a problem.

Ralph White

jet22b

Hi Guys;
I have been in the background reading all the posts and all the good info so far. I think it would be helpfull if someone from Great Planes team who help bring this great plane back to us, tell us why it was not setup to use a 16oz tank right out of the box. In two days my D.B. will be in my workshop and I will be doing the same thing of dropping in the 16oz tank. Over the many years that I have been in this hobby, you will find .60 size engine and up, do not sip fuel, they drank it!!!
Please keep all the good info coming. I will do the same when I start my build!! Big Brown where are you!!!!
Sonny
aka
jet22b

dphill2

My Feedback: (1)

Ralph, Lil Dave is going to use Spring Air 200 series, We both have a set we are flying now and had very good results.
Lil Dave Has a Atlanta with a Long Stroke YS 61 and I'm flying an Omega with the same power.
The only experence I have had with Elect Retracts, I used some Kraft back in the 70s & 80s. They worked fine just a little heavy...

Dave

doxilia

My Feedback: (3)

Oh yea! But how cool are they in their scale staggered movement...

David

dphill2

My Feedback: (1)

Hey David,
I use to flip the switch on the gear as the plane was rolling so the judges could see them as they went up !!! Slow and Smooth !!
Yeah you are right about COOL

Dave ..

doxilia

My Feedback: (3)

yah man!

Gotta get them Multicons back in the Tipo I finished recently... First, the tank, plumbing and engine though.

David

jgg215

Tony isn't the only one with problems on the efite retracts.
I lost my nose gear retract in Bakerfield after seven flights total on my P-7. I think the spectators were placing bets on how many flights it would last....

lfinney

My Feedback: (44)

so whats e-flite going to do about this, i have them in my p7 too not flown yet, is it worth the risk, i have spring airs.....hmmmm no bueno! at the price there needs to be a recall i think.