ghoffman

My Feedback: (3)

Vinnie, we are getting a CubeX 3D printer that can make ABS parts.

VincentJ

I'm not familiar with what the printer can do Gary. Something for work?

I finally completed the firewall. Two pieces of 1/4" birch ply were epoxied together for a total thickness of 1/2". With measurements triple checked I pulled the trigger on drilling everything out. My engine didn't come with a mounting template so a little digging on the internet and I was able to find one. Here's the link for those of you that may be in a similar situation: http://redwingrc.com/engines/images/...20template.pdf

I taped the template to the firewall making sure to line up the centerlines with the template. Using an awl I made marks where the hole locations needed to be drilled. Blind nuts were then epoxied in place.

Cub Flyer Fresno

Thanks for the link VJ.  I'm going to need it as I just bought a DLE 35RA for my SR9.

[email protected]

My Feedback: (1)

very good work just make sure the engine has the center line with the center line on the plane

ovationdave

My Feedback: (16)

Thanks for the reply on the wingtips Vincent. I feel the same way, I guess I just wanted another opinion. Its funny because when I got my GP RV-4 kit, I was really disappointed that the wingtips supplied were of the ABS variety, as I have never liked them. I just thought I would ask since my main reason was always the covering issue. I like to extend the covering to the wingtips for a perfect match, otherwise it looks odd to me.

Keep up the fantastic thread!

Thanks,

Dave

VincentJ

Here's what the firewall looks like after it was epoxied in place last night.

Getting the firewall in its proper position sometimes requires you to use shims of different thickness to get things exactly lined up. So here's a tip I'd like to share with you that has helped me out many times. Keep a deck of playing cards near your work table...the cards have just the right thickness that allows you to stack them to get the thickness you're looking for.

I mounted the DLE-35RA in place and checked its fit and position against the plans and it is spot on! Time to reinforce the firewall on the inside with some 3/4" triangle stock. Then I need to think about the how and where's the throttle and choke servos placement will go before I box myself into a corner.

ghoffman

My Feedback: (3)

You are an "Ace" builder Vinnie, with a big heart!

acerc

Well from one "Ace" to another, index cards are cheaper. LOL

VincentJ

Thanks Gary!

Good idea Ace, you sure you're not a "Yankee"? LOL

This morning I took some 3/32" Birch ply and glued it to each front portion of the fuse marrying it with the firewall. Additionally I drilled five 1/8" holes and pegged the firewall to the fuse with some 1/8" dowel rods ensuring that the firewall is locked into place...

I also thought about how I wanted to run my throttle and I think I have a solution, but before I could start to implement my idea I needed the throttle servo on hand so, off to the LHS I went. I selected a very nice digital high voltage, high torque metal gear servo made by JR (DS3711HV) to get the job done. I don't agree with the philosophy of using cheap servos for the throttle, I want something that will be responsive, smooth operating and hold its position well. Of course it was a bit pricey...[]

acerc

And then you go and insult me. A Yankee, HA! As for your servo size I have no opinion. But I do use a power meter( like the one in the photo) to measure every servo during the build and prior to maiden. Lets me know if there is anything wrong such as a bind, overload, or just a bad servo. But it also lets one see just how little load a standard servo is under for the throttle and choke. It is really cheap insurance. IMHO anyway.

VincentJ

That's a compliment from where I come from Robert! Great minds think alike, this is what I used (servoexciter EF) http://www.vexacontrol.com/xciter_details_1.html

acerc

Those are nice, a couple guys at the field have them. But I always have a Tx and Rx laying around soooooo.

WacoNut

VJ,
I have started using digital servo's on the throttles on all my gas planes even when I am using analog on the flight surfaces. It does help to get reliable throttle changes. I think I spend more time on the throttle setup than anything. These new computer radios make it nice with the throttle curve adjustments as well.

BTW: the fuse is looking great.
Later!!
Anthony

Cub Flyer Fresno

Anthony, I've found out what you are talking about.  I spent a lot of time last week working on my Cub throttle to try to get it more linear!  Unfortunately my current radio, a Spektrum DX6i, doesn't have throttle curve for airplanes, heli's yes, airplanes no.  When I maidened, my throttle went from idle to WOT in about have the stick movement.  Eh, I'm still learning....  

lopflyers

My Feedback: (12)

Nice thread, good looking bird too. 

VincentJ

Thanks lopflyers, I'll keep you in mind when I'm done...LOL

hrrcflyer

Hey CFF,

Lower the endpoint of your throttle servo. That will increase your stick movement............

I am if full agreement with you guys regarding using a high quality digital servo on the throttle. I'm not sure about other engine manufacturers, but 3W actually recommends a digital servo on the throttle for just the reasons you guys discussed.

VJ,
Your Spacewalker is coming right along. Keep up the great work.........

Take care,
David

Cub Flyer Fresno

Yep, I did that along with changing the throttle lever length, etc. It is fairly linear now, or as close as it's going to get. It's good enough, let's put it that way.

Take care,
David

raptureboy

Check out the sticky in the gas engine forum,"gas for newbies". very informative and there are some diagrams for proper linkage geometry so you can get a more linear response. Sorry I'll have to disagree on using a digital high tourqe servo for a throttle , it's just not needed. A good metal gear servo is all thats needed along with the proper linkage geometry. I use 4-40 rod when ever possible, toavoid theflexing of nylon rod,with Dubro 4-40 to2-56 bolt on ball links on both ends so no metal to metal contact and loctite everything. I also have a servo tester but not as fancy http://york-electronics.com/ As always VJ your looking good.

VincentJ

Got up early and fit the two pieces of 3/4" triangle stock to reinforce the insides of the firewall. Once I had them to where they would fit I epoxied them into place.

Attention then turned to getting the turtle deck in place. You can see how I got each former square to the top of the fuse. I did this one at a time waiting for the glue to set before moving on to the next. The first former (nearest the firewall) posed a different set of problems. In order for the former to sit flush with the firewall I had to contend with the two blind nut that were already epoxied into place. Wanting to get the holes drilled in the correct location I installed two screws that if you notice I ground a point on. Taking the former and gently pressing it into place left indentations where the holes need to go. You can see that it worked fairly well.

ghoffman

My Feedback: (3)

Why would anyone not use digital servos these days? Vinnie, did you drill out the standoffs to use one long fastener and those blind nuts?

VincentJ

Yes, that's exactly what I did Gary. I bought some threaded rod which will get some of the red red Locktite to hold it in place.

ghoffman

My Feedback: (3)

I'll give you some Nordlocks, and let me know how long the fastener is.  Matt, me, Cody, etc use grade 10.9 Socket Head cap screws, which I can get from my companies' fastener supplier.

Cub Flyer Fresno

Thanks for the info the Rap! For the price, that tester looks like it would be worth it!

Gee VJ, even the non-critical, never to be seen again parts look fantastic!

Cub Flyer Fresno

Hey raptureboy, this is what I found and how I ended up setting mine up.  Or at least it is really close to that.