Echo on a Funtana....
 

A couple weeks ago I bought a slightly used H9 Funtana. Many people on this site(3D forum) are running Saito 100's on it and the AUW is 5.75-6.25#. I think I can build an Echo 21cc gasser and use some lightening techniques from the electrics I've built to keep the AUW the same. I posted my idea in that forum and not many people thought it could be done. I'll document each step and parts used. When successfully finished I'll also be sure to post in the 3D forum.

If anyone has any ideas I've missed, please post them.

Here is the starting conversion. Steel prop hub, alum backplate mount. 66oz. starting weight

My goal is 30-32oz COMPLETE.

RE: Echo on a Funtana....
 

Here is the same engine with the beginnings of a super light muffler, cut down carb spacer, alum prop hub.

RE: Echo on a Funtana....
 

Here is the carb spacer. I removed the two short, inner(cylinder side) mounting bolts and will order Ti bolts that go all the way through. This also rotates the carb so the throttle is a straight shop. It started out at 1.75oz. and is now at 0.5 and will end up a little lighter after the mill gets done with it.

RE: Echo on a Funtana....
 

Well, first I want to say that I agree with the others that the plane is too small for a gasser conversion, but...

If you insist, you should use the older 23.6cc Kioritz if you can find one. See the "Don't forget the echo..." thread for lots of info. (You will have to do a search for it.)

Good luck, and please keep us posted.

AV8TOR

RE: Echo on a Funtana....
 

av8tor,

I would like to find that 23cc engine but I had 2 of these. These also seem lighter as they only have two cylinder mount bolts and I think the bigger cc ones have four.

I am having ANeat weld a muffler for me. It should be light. The stock one was close to 9oz where the parts for the alum one weigh under 1.5oz. The prop hub in the second pic weighs 0.5oz.

RE: Echo on a Funtana....
 

something else you may have not thought of... 3d planes are not overbuilt, by design they need to be light. pretty good chance that engine is going to rip the plane apart from vibrations... (I just fired up my homelite 25cc on my stinger 1.20 this weekend, pretty much destroyed what I thought was a great glueing job on the firewall. now it is completely glassed with three layers of cloth.)

RE: Echo on a Funtana....
 

Tonight I went over to a friends house and used his lathe/mill. Took a bunch of weight off.

RE: Echo on a Funtana....
 

The cases started out at 12 oz. for the front and rear combo. Now they're down to 7.7oz.

RE: Echo on a Funtana....
 

The cylinder started at 9.5oz and now is 7.75oz.

RE: Echo on a Funtana....
 

The carb runs the engine very well but was porky. So, it went on a diet. I milled away 3 surfaces. Down from 3.75 oz. to 2.75 oz.

RE: Echo on a Funtana....
 

Found these plugs at the friendly local saw shop. Honda/NGK CM-6 plugs. I removed the porcelin(sp) from an old plug and threaded the inside. Med. locktited it in the cylinder and milled away the top for a smooth plug adapter. The stock plug was 1.2 oz. and the CM-6 is under 0.5 oz.

RE: Echo on a Funtana....
 

Before you spent all this time making it lighter, you should have ran it and see if it has enough power to do what you need.
A feather weight engine is no good if it won't even pull up its own socks:D
FWIW The Poulan 18cc Feather weight is also made as a 21cc and a 24cc too. The Poulan 25 is a different engine.

RE: Echo on a Funtana....
 

Share you engine's weight as it is? Too lazy to due as the subtracts and I'm sure you have it at your fingertips.
What did the other end of the crank look like and what does it look like now? Hollow?

RE: Echo on a Funtana....
 

just read that funtana thread and it seems to me that you're on to something good. when considering the weight of the saito+mount+onboard glow power+heavier fuel load you might not be any heavier. and i doubt a saito is any smoother running than the echo. never tried a 15x6 on one of these but it should rev somewhere between 9-10k, which is right where this engine starts making power. have you tried this prop yet??

here's a couple things you may have missed:

the DA/3W plug boots are nice and light and fit the cm-6

you can also save some weight by tossing the mount. just use 4 bolts from the backside of the firewall straight into the engine case.

the rear stub of the crank can also be cut off right at the bearing and the bore for the oil seal plugged. i use the top of an aluminium body from an old capacitor, see the pic.

that prop hub looks SCARY to me!! i would use at least 16mm rod and fit it around the crank. relying on that little threaded stub to keep everything together is asking for trouble.


dave

RE: Echo on a Funtana....
 

ZAGNUT is right about the prop hub, it will alow to much flex and sooner or later the crank will break at the end of the threads.
CH has a prop hub that seats on the taper and uses a stud for the prop.
Another thought put the engine togather and look at the exhaust port. I think that the piston goes below the edge of the port. You can open up the lower edge of the port ( it won't change the exhaust timing) and the engine will run a little better.

RE: Echo on a Funtana....
 

I ran the Echo last year and it is very smooth. I'm guessing that it has less vibration that a Saito 100. I ran it with a 15-8 and was getting around 7400 rpm. If it wants more prop, I'm thinking the MA 3 blade 16" cut to 15". Would look very cool. As far as changing the ports, I think I'll leave it alone unless is seems underpowered.

I agree on the prop hub. I already sent off to have a new one made that fits over the taper and is thicker.

Weight is at 18.7 oz. That doesn't include the crank, piston, muffler, bolts, or gaskets.

RE: Echo on a Funtana....
 

Doug,

Keep up the good work! Whether this works for you or not, you are sharing good and useful knowledge. I applaud you for attempting to do what some folks say is not possible. Keep the updates coming!

Ken

RE: Echo on a Funtana....
 

The overall length of the engine is too long and will put the prop about 1/2" forward too much. I traced the mounting footprint and cut out the firewall, 1/4" spacers, and a new "rear firewall". This will all be epoxied/bolted together to recess the engine 1/2" rearwards.

ZAGNUT,

I am already mounting the engine by the case holes. The pic you posted has four while mine has three. Should be very strong and light.

RE: Echo on a Funtana....
 

I weighed the crank/rod and it is 7.5 oz. The piston/pin is 1.5 oz. As ZAGNUT mentioned, cutting off the rear of the crank should save close to an ounce. I will leave the piston/counterweights alone as not to effect the balance.

That puts the AUW @ 26.7 oz.

Right now I'm taking all bolt measurements and am looking into different fasteners (Ti). All the stock bolts weigh about 3.6 oz. Some shorter titanium bolts will drop that weight to 2 oz. or under.

RE: Echo on a Funtana....
 

How about using a real light glow fuel carb....then you could use gas or glow fuel and save the weight of that heavy walbro carbby! Keep the good ideas and photos coming. Capt,n John

RE: Echo on a Funtana....
 

Keep in mind that because it is gasoline, you can leave a pound of fuel "on the ground"

RE: Echo on a Funtana....
 

Doug, this is a kewel project - lookin' forward to your progress reports. ;)

GOOD LUCK!

RE: Echo on a Funtana....
 

Captn'

Do you mean a normal 2-stroke glow carb such as an O.S? Maybe a 1.08 or 1.20 size.

RE: Echo on a Funtana....
 

Doug....Yup Just about any large glow carb may work. You may have too just experiment to find the ones that work the best. Seems like I read a ASP carb works ok and the price is right.

RE: Echo on a Funtana....
 

Captn'

What about the lack of pumping action in the glow carb? External fuel pump?

These are the pieces of the muffler. 1.5 oz. in the pic.

RE: Echo on a Funtana....
 

"scary" prop hub. New one will be heavier duty. <0.5 oz.

RE: Echo on a Funtana....
 

just noticed that your engine has 4 bolts holding the case halves together while mine has only three. you must have an older engine? that separate ignition coil should also work with the CH ignition kit. that's what av8tor1977 did with his little 16cc echo.

what brand of 15x8 are you getting 7400 with?? mine will turn a crappy MAS 15x10 at that speed using the stock 8.5mm carb. you might be able to gain a bit with some simple porting. the "don't forget echo" thread has the numbers.

i've flown an 8lb 60" stick with this engine and performance was great, at 6lb you should have a winner!


dave

RE: Echo on a Funtana....
 

awesome stuff.

RE: Echo on a Funtana....
 

I don,t mean to be critical...but when posting a reply, could you add more to the post besides a reply like "great stuff" take your time and contribute anything that has some help or imfo another person may use. Or just a few words about what you are working on. Thanks Capt,n

RE: Echo on a Funtana....
 

ZAGNUT,

I'm going by memory on the rpm. I do remember that it liked the 15-8. When I get the motor running I'll build a sliding thrust stand and take rpm/thrust measurements for all the props that'll fit it.

antslake,

Thanks for the compliment.

Doug

RE: Echo on a Funtana....
 

Back to post # 25 I just about missed that question. A pump like a cline may be needed. But I have read where using a small 2oz head tank right up near the engine and level with the needle valve works good. Exhaust pressure is used to pressure-ize main tank. Do some searches...it will be there somewhere. Good luck Capt,n ... Note... 2 tanks are used ,small head and larger main tank

RE: Echo on a Funtana....
 

Captn'

Tank arrangement similar to a glow RC helicopter? What about using muffler pressure into the tank causing an explosion? Backflow into muffler......

RE: Echo on a Funtana....
 

Doug,

If you don't mind an external arrangement, you could build a simple device that would use slipstream action to create your pressure. This would allow for greater pressure at greater speeds and vice-versa. Some of the Pattern guys from the 70's used to do this...Wolfgang Matt comes to mind. (now you all Know how old I am!) Anyway, just a thought...

Ken

RE: Echo on a Funtana....
 

The Iron Bay fuel regulator would solve fuel delivery problems. You can then locate the tank where you please.

RE: Echo on a Funtana....
 

Thanks Eagle Flyer,

I'll search the internet tomorrow for that Iron Bay regulator. Never heard of it before. That's what's so great about this site and the internet in general; a wealth of knowledge to be mined.

I have all the radio gear in the Funtana sans engine, batteries & fuel lines. 3# 11oz.

The TIM-6 ignition is 2.9 oz. complete. That could be trimmed to around 2 oz.

I have a carb from an O.S. FX46. The carb venturi measures 0.302" and the stock WA183A Walbro measures 0.28". ?????? What would have to be changed to use this carb?

Now I'm just waiting to get the crank, hub, and muffler back to assemble the whole thing and test the engine and then fly.....

RE: Echo on a Funtana....
 

The Iron Bay fuel regulator was invented for glow fueled engines to eliminate delivery problems created by odd tank locations. If you are using a gasoline carb, Walbro or the likes of it you shouldn't need a pumping system as the carb already has one built in it.

RE: Echo on a Funtana....
 

www.billsroom.com/pcfs
Jim Cline has the regulator and info on how it works.

RE: RE: Echo on a Funtana....
 

[link]http://www.ironbaymodelcompany.com/Webpages/Accessories/Fuel%20Regulator%20Main.html[/link]

and here's the iron bay regulator. looks like the price doubled since it came out, it used to be half the price of the cline.

the cline reg is about 20 grams and the iron bay is about twice the weight. you will also need some kind of adapter for the glow carb and a tank that can take some heavy-duty pressure. ever seen how a YS turns a tank into a football:D

i think if you add up all the extras you'll need for the glow carb you won't be saving any weight. also, glo carbs can get touchy when trying to run gas through them.

if your stock carb is only 0.28" at the venturi then you might have quite a bit of power to gain by using something bigger, especially if you want to use a higher revving 15x6.


dave

RE: RE: Echo on a Funtana....
 

If you are using the TIM 6 circuit, be sure you have it set up for enough dwell. You can do a search here, and find my posts on that.

Good luck, and keep us posted,
AV8TOR

RE: RE: Echo on a Funtana....
 

av8r,

Thanks. I used your thread months ago for the first TIM unit. In fact I've read every thread on this forum since I signed up.

As far as the TIM-6, I went to the local electronic store to buy two capacitors. They didn't have them in stock so they tried to order just one. The supplier laughed and said they don't ship quantities of less than 100 so they sent a "sleeve" of 10 "pro bono". The guy gave me one and said the rest would be around 17 cents each. Same with the other resistor, about 5 cents per. The rest of the kit is a few resistors, a hall sensor, and a magnet. Supply your own coil, spark plug boot, connectors and your set. Low $

ZAGNUT,

I think you're correct on the 2-stroke carb not saving any weight. For the complexity, sensitive tuning, unfamiliarity, and cost, I think the Walbro is the best option. You mentioned a DA/3W plug boot would fit the CM-6 plug. Do you know where you can find one of these? I'm also trying to source an old capacitor to plug the rear of the case as you did.

Doug