bpryor

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Here are some pictures of the completed installation of a 85cc KS tuned can completely enclosed in the fuse of the Cap. I still plan to put a "spoiler" in front of the canister exit to attempt to create a low pressure area to help pull air through the tunnel to help cool the can. The only thing that didn't turn out as planned was I miscalculated the droop of the front of the exhaust pipe and I ended up having to cut a hole in the cowl to let the curve of the pipe stick through about 1/4 inch. It doesn't bother me, but purists could easily plan ahead and route the pipe slightly differently to get it fully enclosed.

There is a 24oz smoke tank under the 32oz gas tank that can be seen in a couple of the photos.

I'm happy with the way it turned out, and if it works well too I'll be really happy. My only concern is the cooling of the can since there's only about a 7 mm gap around the can to allow air to flow, but if I can get flow through the tunnel, it should be fine.

I plan on flying this week and I'll report back the results.

bpryor

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The gas tank in on its side next to the can tunnel.

bpryor

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The tunnel was complete including the piece turning the exit downward, but it was not long enough with my angled installation so I had to make an extension out of fiberglass to extend it to the bottom of the fuse.

bpryor

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You can see the header and sideways engine installation in this picture.

bpryor

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You can see the angle of the header and can necessary to go over the top of the wing tube.

You can also see Roger Forgues' great engine standoffs in this picture. (Aerografixs - http://www.aerografixs.com)

bpryor

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Here's the exit area in the bottom of the fuse. I still have to add a spoiler in front of the exit to create a low pressure area to help the cooling air flow through the tunnel.

bpryor

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Here's a picture from the rear of the tunnel before closing it off with the exit portion.

stomper

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Hello Bill
How are you sir?

Nice work on the Cap, I'm almost done with mine(DA 100). I am a little surprised you didn't stiffen the fire wall with some ply. Not needed? I would like to try the cans on my next plane (Carden Extra or a Edge). Did you lay up the tunnel yourself? Looks good!

Best of luck with the maiden flight!

Doug

ps your were right about the 2.6 Taurus. Just awesome! Just need to find a suitable gear for the 1/4 Cap. I had some bad luck with a CF gear.

bpryor

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Hi Doug,

>>I am a little surprised you didn't stiffen the fire wall with some ply. Not needed?

I didn't put a doubler on there but I did put triangulation on the back of it, pinned it, added Kevlar cloth on the sides and bottom, and I also put a ton of screws in the top so it would add some strength to the structure instead of just being a cover. I think this will be enough, but we'll see.

>>Did you lay up the tunnel yourself? Looks good!

I wish I could do that good of fiberglass work. The only thing I laid up was the extension on the back of the tunnel for the exit, and it's pretty rough. The tunnel comes from Amelung in Germany and it really is some really nice, light glass work. It is two layers of very light cloth sandwiching balsa strips. It is very light and rigid. 3oz for the whole tunnel except for the extension.

>>Best of luck with the maiden flight!

Thanks. I'll report back here on how everything goes.

>>your were right about the 2.6 Taurus. Just awesome!

I'm glad you liked it. I still love those engines.

>>Just need to find a suitable gear for the 1/4 Cap. I had some bad luck with a CF gear.

Bummer. I've heard of people having trouble with some of the CF gear available delaminating. I assume it was the gear from Troy Built. I've heard their supplier has improved the gear now.

Vince

My Feedback: (1)

Hi Bill, great work.

What did you use for the can? I have been eyeing some large extruded aluminum hair spray cans that the place that cuts my hair uses.

Where did you find the curved tubes?

How much RPM gain have you experienced?

Thank
Vince

bpryor

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Hi Vince,

>>great work.

Thanks.

>>What did you use for the can?

It's a KS(http://www.krumscheid-metallwaren.de/) 89 VS-4. It's their 85cc(max) can and is 65mm X 300mm. This particular one exits in the front, but they have rear exit ones if you'd prefer. In the U.S. Desert Aircraft(www.desertaircraft.com) carries them (that's where I got mine, and would recommend DA highly). Cost is about $135 for this particular model. They are also available from Germany from the manufacturer and Amelung, but with insurance and the poor exchange rates right now, it's just as cheap to buy from the U.S., and besides I like to give U.S. dealers the business if at all possible.

>> I have been eyeing some large extruded aluminum hair spray cans that the place that cuts my hair uses.

Hmmm. I have a couple of thoughts on this that you should consider. First, I would think these cans would be too thin of material. They would either burn through or resonate, or both, and they are probably too thin to be welded or brazed.

You can make your own....but keep in mind that the KS cans are tuned cans. They aren't just a cylinder with ends and outlets welded on, they have strategically placed baffles inside that their positions were arrived out through a lot of testing to achieved some degree of tuning affect. What affect the baffles are creating, and why they affect performance has been debated, but to me, I don't care why, I'm just care that they do, and they do. It's been proven over and over that these cans provide a significant performance benefit over pitts-style exhausts while reducing the noise significantly. By building your own can you may achieve the desired quieting affect(and note I said "may"), but it is highly unlikely you will achieve the tuning affect.

>>Where did you find the curved tubes?

KS also makes the header kit. It comes with a exhaust outlet for your engine, two curved sections, a straight section, a flex section and a teflon joiner with clamps. It costs about $40.

>>How much RPM gain have you experienced?

I can't speak from personal experience yet, but typically on the ZDZ 80 from several other sources it's in the 300 to 500 RPM range. That's not an insignificant difference.

Vince

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Thanks for the info Bill.

Vince

tgladney

Nice work. I am getting ready to do the same thing on the same plane but the engine is a DA100. I liked the glassed tunnel. Does the company have a website that you got the parts from. I believe it was Amelung in Germany.

bpryor

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Hi tgladney,

>>but the engine is a DA100

Have fun fitting two cans in there. Actually I think it could be done, but finding a place for the fuel tank could be the biggest challenge, though I think the right shape one could fit under the cans in the stock location....also the cans on this one would be smaller, but you probably will still need to use the same diameter tunnels. (BTW, I have two KS 70cc rear exit cans that I'll sell, but one is a bit dinged and the other one is a bit worse. Functional, but not pretty...of course you'd never know inside a tunnel)

Here's the Web site for Amelung. The tunnels are under the Accessories category on the left navigation bar: http://www.zdz-motor.de/index.html?lang=en-us

Make sure and put up pictures when you get it done.

bpryor

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I maidened the Cap/ZDZ/KS and the can installation worked flawlessly. At a giant scale fun-fly today at my field, I got many positive comments on how quiet it was...and not only that, people liked the sound. It's not just quiet, but has a very deep mellow sound. Boy, if only all big gas planes sounded like this. (Dick Hanson, if you read this, I must have gotten the header length right thanks to your suggestions, because there were no dead spots and the transition was smooth from idle to top RPM - Thanks! )

There didn't appear to be any heat issues. The can got pretty hot, as you'd expect, but touching the tunnel from inside the plane was barely warm to the touch. This a winning combination.

As has been reported by many people, the Cap flies great. I could only fly the plane on low-rates as I'm having some issue with my trims changing when I switch conditions and I haven't figured it out yet, but I could find out plenty on low-rates. I have a lot of learning to go with it, but so far I like it a lot.

As far as the ZDZ, when it was running, it ran great...but getting it running is another story. It is by far the hardest starting (electronic ignition) gas engine I have every owned. I think that once it gets a little time on it, and I get whatever routine down that it likes, that I'll be able to start it consistently. My take is that it is very susceptible to flooding. Using the typical starting method of choking with throttle at idle until it tries to run, then turn the choke off and flip until it starts does not work because when it tries to start with the choke on it evidently floods the motor....this may be being exacerbated with a bit too rich low end. Bottom-line is that I'll need more time with it to figure out its routine.

Oh, I don't have any RPM numbers to report yet because the environment at the fun fly just wasn't conducive to full throttle run-ups. I'll try it out next week and report back here.

Diablo-RCU

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Bill:
If you are flooding it, try this instead.
Turn off ignition, choke on, 3-5 flips at idle.
Choke off, ignition on, flip at idle until it runs.
If it doesn't pop, probably not enough choking.
Try again with more flips with the choke on and ignition off.
Figure out how many flips makes your engine happy.

bpryor

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Hi Diablo,

Thanks for the advice. This is exactly what I had decided to try. I figure if I can stop flipping with the choke on 1 flip before it would have run, it would then start quickly with the choke off. I'll pretty sure I will be able to figure the flip count out with a bit of practice.

Thanks.

stomper

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Glad to hear you had a successful maiden with That Cap! I'm going out with mind today. I put the choke on a variable knob on the transmitter so I can adjust the amount of choke. I don't know that It was needed with the DA, just the way I set it up.It's good to hear the can worked out for you , I will have to try them on my next plane. What oil are you using for break-in?


Doug

rmh

Glad it all worked out- as for the starting - sounds like a carb which is rich on the bottom end. Typically, they not hard to start.
A suggestion - IF you cannot sort it out -
I found from doing a few engines - that the carb -in the majority of "hard starting " events --is the problem - not ignition. I have yet to see one of the new series Falkons fail. Except crashed ones --
I use a WJ38A on one 80 -and it is a one flip starter --BUT IF I flood the engine - It takes some flipping to clear.
I only flood it when I forget to turn on the ignition--
Typically choke on - idle - lazy flips not too many - it make s a few grumbles - then choke off - a few lazy flips and it starts and runs easily and smoothly -at idle.
Most Bings -the same - but idle not as smooth.--has to do with getting the idle lean enough - yet not too lean to give instant recovery -
The Walbro seems a bit easier to adjust for this.
The engine - once run for the day - requires only a single pull to restart.
Note that this is NOT a restart when engine is very hot from running extended time on th ground - but after a flite -then a cool down.
That is fairly typical on gassers anyway .
Try leaning the low needle untill warmed up acceleration is starting to gasp - then tweak back the other way .
Typically low end is correct when the idle speeds up and smooths out.--thru leaning the low mix a little at a time -
That's also common on most gassers.
There are a bunch of 80s/40's here and this is the typical condition .
My new 100 twin should be here very soon - Now to do a scratch and sniff comparison with the 80 single!

bpryor

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Hi Doug,

I too set my choke up on a slider, but it didn't end up serving any purpose. Only on and off seemed to be useful. I used Castrol 2-cycle ashless petroleum based oil, which I'll switch out to synthetic(I typically use Amsoil 100:1 or Klotz) after the first gallon as recommended.

Hi Dick,

Thanks for all the tips. I think you have confirmed what I suspected that the low-speed needle is too rich. I did "tune" it of course, but I could easily be on the rich side at this point. It had a little "bog" off idle if fast throttle was applied, but it also seemed to have that at various settings, so I think I might have misinterpreted that as being lean. I'll fool with it next time when I have a bit more freedom to fool with it. The timeline for flying was at the fly-in was not conducive to fooling around with tuning.

lewdfinger

My ZDZ 80 has no hole in the choke plate, so flipping until it pops floods it without fail - plus i get gas dripping out of the carb into the engine box.

My method (I have 3 gallons of gas thru it now, high octane, Klotz 50:1):

1. 1st start of the day - idle, choke on - 2 flips then choke off, throttle one click open. Usually starts on 2nd or 3rd flip thereafter. If it doesn't start, or starts and starves, I choke it for one more flip MAXIMUM.

2. Warm starts - One flip with choke on, then choke off, leave at idle - starts with one lazy flip 99% of the time.

I love this engine!

KD

bpryor

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Thanks KD. That's the exact procedure I was going to try, but I had no idea where to start on how many flips with the choke on. I'll let you know how it works out on my engine. You didn't mention if you have the ignition on for the initial flips. I was planning not to have it on to prevent it from firing while the choke is on.

lewdfinger

I just leave the ignition on. Sor far it has not 'popped' on the first two flips - seems to take at least 4-5 flips until it fires while choked.

KD

bpryor

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For those interested I took some video of my Cap today so you could hear the exhaust note. Unfortunately it ran out of video right after I took off, so a little warm up and the takeoff is all you'll hear, though it will still give you a good idea of the sound. There are two files, both are in Windows Media format. One is lower quality and smaller (700K - http://www.hidenseek.com/cap232-1.WMV ) and the other one is higher quality and bigger (2.4M - http://www.hidenseek.com/cap232-2.WMV ). The sound and image quality of the bigger one are definitely better and they will stream if you have a recent Windows Media Player.

BTW, I tried the suggested starting procedures and I had a much easier time of it this time. From cold it ended up taking 5 flips with the choke on, ignition off, throttle closed, then about 10 flips with the choke off, throttle a couple of clicks off idle and of course the ignition on. When it was warm, it took a couple of flips with the choke on and about 5 flips with it off and ignition on. Much more acceptable. It just appears to be very easy to flood and you have to be aware of that and everything will be reasonable.

Oh, and when the engine was hot after the first flight, the engine turned 6450 on the Mejzlik 26X10, which seem pretty good for less than a gallon of fuel through it.

On a little less positive note, the Cap is history. The first flight today was flawless, then about 5 minutes into my second flight the plane started rapid(but not fast like flutter) porpoising without any ability to control it. I was up pretty high and had time to try a few things, but there was no elevator response no matter what I did. All other controls were working, but it gradually decade into a vertical porpoise straight into the ground. It's really toast. The Truturn spinner looks like an accordion, the exhaust header is spaghetti, and one of the engine mounting tabs on the engine broke off. I'm sure the crank must be bent. About all that survived intact is the radio gear. All the servos appear to be intact, though I haven't tested them, or the receivers either....and yes, two receivers with one elevator half in each receiver and it still had no elevator control. Very strange. It was not flutter. There is no sign of damage in the rear. The tail is totally intact and everything is in perfect shape. I'll hook everything up and try it when I get around to it, but right now it's all in a pile, and probably will be for awhile. Oh well, that's part of our wonderful hobby we have to accept, right? It's a real bummer, as I was really starting to like this plane. :cry:

stomper

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Bill I am very sorry to hear about the Cap! When you sort It all out I would like hear what went wrong. Mean time I think I will be taking It easy with mine. What hardware were you using? (push rods/links) I'm very sorry sir!


Doug