RE: composite arf yak?
 

I would get equal length standoffs; sounds like they did all the engineering into the firewall.

RE: composite arf yak?
 

Right thrust is built in.....just get equal length standoffs.

Kevin

RE: composite arf yak?
 

Hi Paul- sorry about the delay on the exact length of the servo leads. I was called out of town.
Got back tonight ( right to HERE ) I will measure tomarrow.
As far as the thrust in the Yak, there is right thrust built into the engine mount. Mine is EXACTLY 1 1/2 degrees. Down thrust is SLIGHT MAYBE 1/2 degree ( why bother? ) As far as the spacing from fire wall to prop, I milled a piece of 3/8" ply the EXACT shape and size of the attached mounting plate on the DA engine. That puts the PROP at 5/8" from the cowl lip.
I went 1/8" more than the 1/2" to bring the engine a little more forward. Anyway it looked good to me at the time. LOL Paul, did you see my " tape " estimate of the servo leads in the above thread? Like I said I will give exact tomarrow. For exhaust we are using the KS tuned pipes and headers. VERY long system; 38" from centerline of header to tip of pipe. This system is a bit pricey, ( $422.00 ) but people I have talked to said it WAS THE BEST. Even DA said they are. I tried to post some pics, but it did not work. I'll fiqure out why and send. Also I already have the rear bulkhead mount made. I used a "suspension" mount. They turned out pretty good. Had to design and build myself, because no one had any to buy ( out of stock? )
So..... all for now. I will be back tomarrow nite. Paul?
Vicster

RE: composite arf yak?
 

By the way, how much does DA charge for extension? Maybe I should sell some plywood DA 100 extension plates! LOL LOL[img][/img][img][/img]

Vicster

RE: composite arf yak?
 

Hey Vic,
No rush on the servo extension lengths. I would like to order them this week sometime, but no real rush.
I do have one concern now though. You say that you used a piece of 3/8" thick ply for your standoff mount.
The DA100 is 6.5" from back of mount to prop hub. If you used 3/8" thick ply, then the back of your prop would be 6.5" + 3/8" from the firewall. This equals 6 7/8" total.
Back on the first page of this thread a guy named Kevin (username Eruption, I think) says that from firewall to cowl lip is 7" exactly.
Somehow the numbers don't add up. I'm missing something here.
Kevin?
Maybe I'm just mis-understanding one of you guys!
Can anyone help?

Thanks for everyone's help so far. I love this thread....

RE: composite arf yak?
 

Hi Paul- First I apoligize, the plate I made was 1/4" thick, NOT 3/8".
These are the specs of the Yak I have. From firewall to lip of cowl: 6 1/2". DA engine mount to
spinner back plate: 6 1/2". ( exactly the same ) From firewall to BACK of spinner plate: 6 3/4" From firewall to FACE of spinner plate: 6 7/8". I don't know where I came up with the other
dimensions ( brain fade ) That puts the prop 3/8" from the cowl lip. ( not 5/8" )
See attached drawing ( if it goes through )

Vicster

PS servo leads tonight

RE: composite arf yak?
 

[img][/img]

RE: composite arf yak?
 

[img][/img][img][/img][img][/img]

RE: composite arf yak?
 

Here are more pics I finally fiqured out how to post a pic!
Vicster

RE: composite arf yak?
 

Some more.......

RE: composite arf yak?
 

Thanks Vic.
Now maybe Kevin will chime in, and let me know what's up with the 7" measurement he posted.
Maybe each plane is a little different????
Anyhow, IF anyone is willing to make me one of those standoff plates from plywood, I'd be willing to pay a little for it.
I would make one myself, but I don't have the saw to cut it out, or a good sanding method (other than by hand.) to make one. Just an offer.

Thanks Vic,
Did DA tell you what kind of rpm gain to expect w/ the KS pipes?

RE: composite arf yak?
 

Paul,

I just went out and measured the distance from the firewall to the cowl lip. Mine was only 6 5/8".

I swear the prototype was exacty 7". I measured and remeasured to make sure. In fact, I went out and ordered some standoffs from Roger Forgues to speed up the building process since I "knew" the correct measurement.

I just put the standoffs on, and took a few pictures. The cylinders just fit inside the cowl. I will probably stick with these stanoffs until I get an accurate CG measurement. If it comes out slightly nose heavy, I'll get shorter standoffs.

RE: composite arf yak?
 

Kevin - That's a sweet looking engine, it looks familiar he he. Hurry up with a quick and dirty mock-up to see where CG will be on yours, please. I want to know for when my Yak comes in, on the next shipment.

Vicster - Thanks for the pictures, looks good, awesome pipe set up, how are those louvers coming he he.

DKjens

RE: composite arf yak?
 

Thanks Kevin,
I'm actually relieved to see yours is about the same as Vicsters. Maybe the prototype was different.

RE: composite arf yak?
 

Hey- here are some more pics. Notice the prop clearance,
Paul, if you want, I will make you a engine spacer. Tell me which engine and thickness. You pay the postage.
Paul- the servo leads ( receiver in front of wing tube ) from elevator are at 52". You may have to make some up. Out board aileron lead is 30". Inboard is 18".
I will post pics of vents as I do them.

Vicster...........fly low-point straight up.

RE: composite arf yak?
 

More pics........

RE: composite arf yak?
 

Guys,
This is the first Composite Arf I have owned, and I was noticing in the instructions that they recommend using milled glass fibre mixed with epoxy in various areas.
Is this necessary? Who is actually doing this?
I was planning on using regular Z-Poxy or BVM AeroPoxy.
Thanks.

RE: composite arf yak?
 

Hello:
What header drop length are you using Vicster?

Is there enough space for some MTW cans which are 2.75" diameter a piece in the tunnel?

It all looks good.
Thanks

RE: composite arf yak?
 

Great Job Vic!

I just got back from the Nall and I really thought the Proto Type 2.6m Yak would be there with its owner, but it wasent [:o]

I spent a little time discussing this plane with a few people that designed it and the Stock wing tube it a great tube and super strong to handle all the punishment you can throw at it.

Paul Cataldo I missed you man, Bob said you were around but I just couldnt find you, man was that just an AWSOME event or what?

RE: composite arf yak?
 

Yeah Darcy,
Bob told me you were around too, but I never saw ya. I had to leave Saturday pretty early to get back home, but yes the show was awesome.

RE: composite arf yak?
 

Paul- concerning the milled fibre glass: USE IT! It creates a VERY strong bond. I used it for all the control horns, the bulkhead mount for the pipes and anywhere else a part will touch the skin. Another name for it is "micro-balloons". A good quality MB is milled FG.
Be sure and use the BEST epoxy available to you. BVM is very good.

Vicster

RE: composite arf yak?
 

Hey Guys- remember we talked about doing the cowl vents? I said I would post some pics?
Well, the first one I did is not worth a picture! I have a lot of work to make it look decent. Unlike any thing lexon ( clear plastic ) that has been vacuume formed I have seen, trimmed or painted, this is the worst I have seen. Now mind you for a kit, they are OK. BUT,
they paint them from the OUTSIDE ( not the inside, maybe to match the rest of the paint ) There were also a few bubbles at the "base"of several vents.
It is thick and hard to cut with exacto #11. BUT... the secrete is to try to cut at the very apex of the corner where it is the THINIST from being pulled over the mold. If you take your time, I think they will be OK. I'll let you know tomarrow when I do some more. MAYBE a picture!

Vicster fly low, point straight up

RE: composite arf yak?
 

Hey Vic,
Sorry to hear about the cowl vents, I hope that we all don't end up screwing those things up!

As far as the statement you just made about the milled fibre/ micro balloons, well I have to say I'm confused. (Unless I'm mis-understanding you)
It has always been my understanding that milled fibre will strengthen any epoxy joint and microballoons will slightly weaken any epoxy joint. The use of microballoons is to create a lightweight joint that is easily sandable. Such as a fillet.
Someone correct me if I'm wrong, but I hope you didn't use microballoons for strength.
Go to www.bvmjets.com and look in the lower left corner for "tip and how-to's".
Then go to "gluing is important".
This is Bob Violets home page and he explains the above.
Forgive me if I have appeared to be offensive, as I just want to get to the bottom of this! I assure you that you guys are generally more knowledgeable about this hobby than me!

RE: composite arf yak?
 

You need to use Milled FiberGlass, and not Micro Balloons, big difference.

RE: composite arf yak?
 

Paul, you are ABSOLUTELY correct about the milled glass vrs. the micro baloons. I APOLIGIZE for the mis-information. I was mis-informed and did NOT check the containers contents
decription. I DID use milled glass ( see pics ) ANYONE who read that thread, PLEASE DISREGARD!! Thank you Paul, for catching my BLUNDER and pointing it out. I must have had brain fade ( again ) Maybe I was over come with airplane fumes! NAW.......old age!

Vicster