DR-1 (Sands): Builders Group - Page 228

Jim Bruton · 17 June 2008, 06:40 PM

Steve,

that's what I am using too, only difference is mine is a flat mount. i figure i can always change it out in a few years, if i feel the need.

Jim

Dogtail2 · 18 June 2008, 12:00 AM

Thanks to all.

You should see the size of the scrap pile trying to get those chutes right!

Jim,

With regards to the Lycoming engine mount, as I understand it, there is Dynafocal 1, Dynafocal 2 and Conical. I think 'Flat mount' is the same as Conical mount. I could be wrong here so somebody else might confirm.

Pete

Jim Bruton · 18 June 2008, 04:50 AM

Pete,

By "flat", I am referring to that referred to in the plans. Looks pretty flat to me, as opposed to Ed's which is definitely a dynafocal, with the angled attach points. Those attach points are what I believed were the reference for "flat". I'm with you- if anyone can shed more light on the terminology, that would be good!

Jim

fighterjock44 · 18 June 2008, 05:30 AM

Pete, Jim,

I have always known flat and conical to be the same also. I decided on that mount configuration since Ron Sands recommended it of using a Lycoming. Plus having more room to play with the engine mount moment arm to help the cg location.

Steve

Jim Bruton · 18 June 2008, 06:07 AM

The next trick will be for you to find an engine that is rear-carb configured, or modifiable (sp?) to that.

Mine is an O-320 B1B. maybe that helps.

Jim

fighterjock44 · 18 June 2008, 06:22 AM

Jim,

Yes, your engine model number does help alot. I was told by a few pilot friends that helicopters use alot of the conical mount lycoming engines. But I am not sure how they configure the carb system.

Have you picked out a prop yet?

Steve

US95Damiani · 18 June 2008, 06:42 AM

Hi Jim,

I've never heard of it being termed a "flat" mount, but the conical mount Lycomings have an even or "flat" mounting arrangement. Conical alluding to the type of conical rubber bushing used to insulate the engine vibrations from the airframe,

The angled type mount is called a Dynafocal mount and uses large rubber/aluminum insulators and there are 2 types of that mount Type 1 and Type 2 LOL.

As far as rear mount carbs, Most fuel injected lycomings from say a Piper Arrow will have the injector mounted to the rear. there are only a few rear Carb types, and they use a side draft type carb the HA-6 which is commonly found on the O-360-F1A6 in a Cessna 172 RG. O-320's you'll find the engine from a Twin Commanche will have the rear mount since it was originally fuel injected. I'm not sure what mount type it uses.

If you are converting a Constant speed prop crankshaft engine to a fixed pitch, you'll need to get your hands on a copy of Lycoming Service Instruction S.I.1435 which is available on the Lycoming website under the support link.

Jim Bruton · 18 June 2008, 08:55 AM

Steve,

I have contacted Culver props about making me an Axial-ified prop. They can push it up to 84" I think, have done it before, and the last price quote was $625. I have the Axial transfers waiting.

US95Damiani- thanks for the insight. I do have the HA-6 carb and this will allow me to use the holes in the side cowling.

Jim

Dogtail2 · 18 June 2008, 09:10 AM

Good stuff US95Damiani, Thanks.

Jim, where do I get Axial transfers?

Here is a shot of the Narkunas built DrI with a normal front mounted carb. Looks ok I think.

Dynafocal mount on the same Triplane

Jim Bruton · 18 June 2008, 07:26 PM

not sure where to get the transfers Pete- i got a set from someone in Canada. Does anyone have good enough art from which to make more? Just now I can't find them but if and when i do, I'll scan them for you and maybe- worst case- you can make your own.

back to you on this later.

jim