Left side truss complete and ply stress plate marked for new wing tube location and lightening cut outs.
I precut and fit the right side trusses while building the left side so even with the plans and jig both side will be exactly the same. This should also make building the right pretty fast. The new wing tube cut went well. I drilled and screwed all the ply stress plates together to keep them from any movement during the cuts, it worked well all matched exactly. I wish I had a better (cleaner) method for cutting out the lightening holes/areas than my dremel and sandpaper. Besides using a milling machine are there any better tips on doing this job? Could I turn my drill press into a mill? The lightening cut out worked OK but IMO look a little butch, I gotta find a cleaner way for the next build.
I want to set up F1 (firewall) length. Should I run the backing plate for the engine out just beyond the cowl, or take it all the way to backside of the spiner depicted on the plans? The backside of the spiner sits 5mm beyond the front of the cowl on my plans.
I use a scroll saw to cut all the lighning holes, tape the two sides together and cut both of them at the same time. As for the spinner. I would leave a 1/4" gap from the back plate of the spinner to the cowl. Keep in mind that because of the right thrust the propeller can hit the right side of the cowl if not spaced right. If you haven't glued the firewall yet you can build in the right thrust in to it.
Posts: 736
Joined: 11/1/2002 From: Laurel,
MD, USA Status: offline
I'm enjoying seeing this go together. Way back when, when Carden first started selling this plane, one of the guys at my field built one with a D&B 3.7. JR 4131 servos. It was only like my 2nd year of flying and I couldn't stop drooling over it. Guy was a first rate builder- just an awesome, awesome plane. He let me fly it one day and I couldn't believe how good it flew. Up til then I had never flown such a large plane. I was hooked. My next build was a 1/3 scalelaser scratch built from Ulery plans- and I've had three Cardens over the years.
I remember him saying that he would be upgrading to the 4721's that were just coming out. I thought he was crazy to put so much money into servos.
Posts: 2
Joined: 11/22/2007 From: Monroe,
GA, USA Status: offline
Doug, Looks like you are "into" building the Carden. I appreciate the updates. I bought mine (30 % Extra) used and it quite heavy but, it flies very good. Landings are a challenge for me because it is heavy. All the lightening you can do will pay off.
Moving the wing up will give a bit of strengthening to the wing tube mounting. I've had to reinforce this area on the low wing version.
Something else to look out for is the firewall mounting scheme. I'm building a new one from scratch and trying to lighten and strengthen, but my tendency is to add something that probably isn't needed.
Posts: 116
Joined: 6/20/2006 From: Hastings,
MN, USA Status: offline
A scroll saw eh, I guess that brand new saw my father-in-law got two years ago (that is still sitting in its box) will find a new home in my shop. I haven't glued the firewall yet so I will take your advice with setting the thrust, it has always work well on my other models, thanks Albert. Here is a dumb question, on all of my nitro models the back of the spinner and thrust plate of the engine were basiclly the same point. This is my first gasser, does the back plate of the spinner on a gas engine align in the same maner?
Thanks guys for your help, please check back often I will have more questions.
I had to do it, I couldn't wait. So I dry fitted the fuse to see how my new location for the wing tube would align. Just the way I wanted, all square and all level, whew! After having a cold beverage and admiring the fit I pulled it apart, cut some lightening holes in the gear plate, and glued it in with cross trusses. By tomorrow the main box of the fuse should be solid and square and I can work on moving aft with the cross trussing. By the way, NO those are not extra wing tube holes throughout the airframe, my forstner bit just makes the perfect clean holes for lightening.
Posts: 116
Joined: 6/20/2006 From: Hastings,
MN, USA Status: offline
-17 temps last night and only warming to 1 above today will give reason for anyone to want to stay in and build. I dry fitted the truss stress plates and wing stress plates again to be satisfied with fit and then epoxied them all together. After checking all was square and level, left it to dry (how many clamps can you count?).
The instructions want me to fit the turtle deck before installing cross trussing from F5 back to the tail. That means I need to start some sheeting and set the fuse aside for a few days. I plan on installing balsa caps on foam edges prior to sheeting to give a nice seamless finish.
This brings back memories, the first one of these kits I built was in 1991 just after I graduated from high school. If I was to do it today it would have a 50cc engine and the lighest accesoriesI could find, it would be great at 18 pounds or less.
any idea where I could buy one of these 30% Carden 300's these days?
Right here, would you like one covered in the patty scheme and ready for paint never flown or would you like a kit with the invoice from 1991 still in the box ?
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RE: 30% 300S mod to mid wing? - 
Just the way I wanted, all square and all level, whew! After having a cold beverage and admiring the fit I pulled it apart, cut some lightening holes in the gear plate, and glued it in with cross trusses. By tomorrow the main box of the fuse should be solid and square and I can work on moving aft with the cross trussing. By the way, NO those are not extra wing tube holes throughout the airframe, my forstner bit just makes the perfect clean holes for lightening. 
