John C

I started a Shockwave probably 20 years ago, and have carried it with me through several moves. I saw this plane mentioned in another thread several days ago, but I need some incentive to complete it. Plan was a Cox TD 049 for power with a 1 oz Veco tank. I see where pen bladders are recommended for pusher applications, but I have no info on the details of doing this. Any help here?

My other concern was my arm getting chewed up by the LH white plastic props (Girsh?) that I also have, when hand launching. Can I get some assurance this does not happen [8D].

I was originally going to use Kraft KPS11 servos - an indication of how long this plane has been around. Fuselage is basically complete, as are the wings.

Any flying experience would also be appreciated...now I wish I had a .049/.061 Norvel R/C engine to use on this plane...I expect my .074 is too much

Thanks in advance for all responses

ajcoholic

My Feedback: (10)

Can you post a pic of the plane so far? I dont know what a shockwave looks like.

AJC

John C

I'll get the box down tomorrow and shoot some pics....then try to post them

combatpigg

My Feedback: (3)

HI JOHNC! First, let me give you my opinion about how to power the SHOCKWAVE!! NORVEL .074!! It looks to big and heavy for even a hot COX TD 051. I can't say for sure because I never got past the" looking at the plans and laughing stage at the recommended power stage", but there's no way I could make one come in under 13ozs and have any structural integrity. That's got to be your target weight if you want unlimited vertical out of your TD 049. Now I CAN tell you about hand launching a pusher. First, if you have any doubts, wear a heavy glove, but if you have a decent follow through, your hand will clear the 6" prop OK before that part of the ship passes by where your hand once was. Now BLADDERS! You will need to go to a fishing tackle supply[ K MART] and get some 1/8" latex tubing. You want to cut off pieces of small brass ,aluminum, or even hard plastic tubing to make anti crush sleeves out of. Make sure to smooth the outside edges of the tubing so it doesn't cut into the fuel line. I use a rubber honing wheel on my bench grinder to put real nice rounded ends on tubing. The last item you will need is some of the smallest TY RAPS you can find[RADIO SHACK]. Tie a knot 3" from the end of the latex tubing and clip this hunk of stuff off. You might as well repeat this step 6 times. so you will have fresh replacements when you go flying.Now put some spit on one of your crush sleeves and insert it into a hunk of small silicone fuel tubing. OK, now you're ready to insert the reinforced tubing into the open end of your bladder, and tie it off. But you aren't done,, you will need a 2 oz syringe to inflate the bladder with fuel. I go to the local CO-OP farmers supply for syringes. You want to get a couple of short sheet metal screws and install them in the syringe body so you can't accidentally pull the plunger out while you are filling the syringe. You will also need a short hunk of brass tubing to push into the end of the syringes' plastic tip so you can work with the small fuel tubing. I think I use 3/32" tubing for a snug fit into the MONOJECT syringe. Don't buy the style of syringe that won't allow the insertion of this tubing and make sure you round the outside edges of the brass tubing! OK, one last item is to get a hemostat surgical clamp. Set the needle for a drip rate of about 2 drops per second. You can prime the engine by burping the line as you turn it over. It's easy to flood! It is very easy to fry an engine if you are using a worn out bladder, look for signs of stretch marks, or any "aneurisms" Don't over inflate. You might have to train the bladder to inflate from the rear . ALWAYS wear goggles. ALWAYS work the needle adjustment from the rich end ! You could route the tubing through a mouse trap like device that is servo actuated for a shut off. My finger's tired, so here's a shot of how this stuff looks, and GOOD LUCK!

John C

Combatpigg, thanks for all of the info. If I understand correctly, the 1/8" ID latex tubing is placed over a piece of metal tubing that has fuel line on it. This 3" of latex tubing expands enough to hold 2 oz of fuel...no wonder you look for splits/anureisms

For AJ's sake, the Shockwave is RCM Plan # 750. It uses a Ace Pacer wing with sweep and a long fuselage and pusher engine. Aileron and elevator control. This yeilds a 35" wingspan and 33" long fuselage. If I go with my Norvel .074, I'll also want throttle control

I've included a picture of plane and plans below - I f I did this right

ZAGNUT

My Feedback: (1)

looks like there's no point in using modern micro gear, all the weight saved would probably have to be added back to the nose for balance


dave

combatpigg

My Feedback: (3)

HI JOHNC! As far as I know, the only practical way to make a high pressure bladder work with a variable speed carburetor is to have a diaphram actuated pressure regulator. It is basically a ball check valve that opens and closes with every pumping cycle. The bladder feeds the inlet, and the outlet is nothing more than a "timed" spurt of fuel. The trick is to calibrate it to give your carb fuel delivery at just slightly above atmospheric pressure. I think AJC could make you one of these back plate mounted regulators in about 5 minutes! The SHOCKWAVE!!! is sooooo long that you should be able to fit a tank just on the other side of the firewall and still maintain your CG. Keep the tank small [2oz] and you will have fewer fuel gravity problems when you point the plane up or down. A 1oz tank would be even better, if you could arrange inflight refueling. Again, I think you should contact AJC about having him convert his contest entry into a refueling tanker! Those ACE wings are made out of heavy injection molded foam aren't they? It was so long ago when I built their GLH, that was my first "hot" plane. I can't wait to see your finished product, because the SHOCKWAVE!! sure is hot looking on the drawing board!

John C

I may have to try with a regular tank and the 074 first as it draws well. I also found an Ace Pacer wing today in my searching...haven't found any plans yet though. The Pacer was my first 1/2A R/C plane other than powered gliders...remember the Ace High ?!