Well today was the day. After much frustration with the Saito 170R3 (now I remember why I haven't used it for several years), I got some air under the Waco's wings. The 170 has far more power than the model needs, even when it dropped a cylinder, power was more than enough. Even though I'm using a Sonic-Tronic's on-board glow, the engine kept dropping the cylinder that's at the 7 o'clock position (looking at it from the front). I'm using a 4-cell 4500 Nimh and it's not giving out enough amps to keep the plugs hot enough. Does anybody have any suggestions on how to keep all 3 cylinders lit?

Here's some pics.

FB

Here's some detail shots of some of the changes I made to the model. I added flying wires, cockpit coaming, the black rubber around the wing fairings and landing gear cuffs. I did away with the servos in the upper wing and added aileron slave rods to activate the upper ailerons. Also, I need to finish fitting the cowl (engine fits perfectly inside), and paint and add the pilots.

Here's som pics.

FB

FB, awsome job of detailing your WACO, looks fantastic. ACF

Check this out.
http://www.nelsonhobby.com/advanced_glow_switch.php
I have been using these for many years now. I have never had a problem with the battery life as it only comes on if the plug starts to cool. Never lost an engine when using this device. You would need a single cylinder model and a twin cylinder model. While I have never had a 3 cylinder engine I have used both the one and two cylinder units and both worked as claimed.
Fred

I received the ring exhaust from Keleo Creations and it looks great. I have not had a chance to test the fit; it was a great weekend for flying so building did not happen. It has the main exhaust coming out at 9 o’clock and does not go back as far so it should clear the fuselage unlike the standard ring. I should get to it tomorrow evening.

As for the Sonic Tronic Glow System, I have one on my 60 sized TF-SNJ running the Saito 90R3 and saw the same thing with a 4-cell 4200. I changed it to a 5-cell 2600 NiMh and it works fine. Obviously that is not supported in the documentation, but it works. I have several flights on that system and mine is still okay. I thought mine was maybe weak, or something, but now I think a call to Sonic Tronic might be in order.

I promise to have photos tomorrow. FB your aircraft looks great.

Thanks for the kudos guys!

Fred: Thanks for the link! It looks like a good solution. Have you linked two of them together? If so, how? Also, does the unit run of off the Rx battery pack? Thanks!

n6iap: Hmmm....I thought of trying that but didn't want to let the magic smoke out of the unit. Stepping up the battery to a 5-cell will be my next step. If that doesn't work, I might go with the above suggestion. BTW - why did Keleo put the exhaust at 9 o'clock instead of at the bottom? Thanks for the battery info!

FB

Fred, totally agree on the Rx pack. I looked at the unit on Nelson's site and it looks like the driver plugs into the Rx. There's no mention of using a separate pack for the driver. How did you install yours? TIA!

FB

Well it is time to go back to the drawing board. The ring exhaust I wanted to use does not fit and it looks like the modification necessary to make it fit is not going to be easy. I want to thank Free Bird for posting his photos; they helped me to see something I missed. When taking measurements for clearance on the ring I forgot to take into account the wooden cowl brace attached to the fuselage and the glow plug driver caps. If you look close at Free Bird’s second photo in the first group, you can see there is not much space for the exhaust, wood ring and glow plug wire housing.

I am going to mount the engine again without the exhaust and take measurements again with the plywood ring and glow driver installed. BTW, the reason I asked for the exhaust exit at the 9 o’clock position is to match the aircraft in the photo. As you can also see from the full scale example, there is a gap between the fuselage and the cowl, which could solve the clearance issue. I’ll update after I decide how I will move forward.

I included photos of both the standard Keleo ring and the custom so you can see the difference in clearance between cylinder head and exhaust.

Ahh...now I understand why you wanted the exhaust to exit at 9 o'clock, sure would have been nice. I've been looking at the boot cowl and the collector ring, and it looks as if the entire front of the boot cowl were removed and opened up to its widest point, the collector might fit. Only problem there is that you lose the hidden mounts for the cowl. You probably could go with the old/standard way of using wood blocks and screws through the cowl. It's something to think about. Thanks for posting the pics of your collector ring n6iap.

My pilots should be ready on Wednesday, I'll post some pics when I get'em.

FB

n6iap

Just for info, the red Waco with the Question Mark on the side is a 1932 Waco CTO, NC 280W with a Wright 975E&F-2&3 9 cylinder engine (modified). The engine in this plane is rated at over 500 hp and held the climb to altitude record for many years.

P1 an overall shot of NC 280W
P2 Doing what it does best, climbing for the skies

You can find the complete instructions on the following web site
www.southhertsmodels.com
Fred

Awesome! Thanks Fred!

FB

I want this plane...bad

Ditto!! I guess we are all in line for now!

I have one I'm flying with Saito 180 gas and another in box...

R/C Foolish

That has to be seriously overpowered! Mine with the Saito 170R3 was far too fast, even with a cylinder out!

FB

I'm going with a Saito 125A for mine. It should do the trick pretty well.

Nope, flys great!!!

Free Bird et al,

Just got off the phone with Hank at Sonic Tronics. He indicated that our problems were as a result of not having enough amperage to drive all three cylinders. He said we should have 1000 mA for each cylinder and that was why my 2300 mA 4-cell was not enough to keep things hot. I am going to try a 4200 mA 4-cell that I have but it will be a couple days before I can report.

He also said that the only reason the 5-cell did not blow out a glow plug, besides being very lucky, was because I left part of the “servo wire” on the battery, which offered enough resistance to lower the 6 volts. Battery not being charged to maximum and only run at start and 1/3 or less throttle also helped.

Hope that helps, buying a new 3000mA or greater 4-cell battery is the cheapest of solutions so far presented. BTW, Hank invited anyone to call if they had more questions.

jimm

They are out there, I found one. I may go buy it tomorrow. Any thoughts on a Saito 150 for it?

jimm,

While all of this sounds good, my experience has been contrary to the above. I'm using a 4-cell 4500 nimh (I know the instructions say to use nicds). However, none of my LHS had nicds of this size on hand, only nimh, so that's what I used. But, let's think about this for a moment, each plug requires 1.5v and about 3amps to be properly lit. That means that the pack needs to supply 4.5v and around 9amps continously for a 3-cylinder engine. Under these conditions, I think a 4-cell 4500 pack is already over taxed, hence the low output on the plugs. I think the way to go is to use a regulated 2-cell 25c lipo. Voltage would be around 5v (a 4-cell hot off the charger is over 5v), and the pack would be able to supply the necessary amps without any problems. I'll be checking with my LHS this weekend to see if they have the necessary stuff.

Hill202: A Saito 150 IMHO, is way more than the model needs. Mine with the 170R3 was a lot faster than scale and I flew the first flight at around 1/2 throttle.

More to come..........

FB

Thanks Free Bird. I think I'll go with a OS 120, that is if my LHS has not sold the plane. I do have a OS 95, that might would be enough.

Just went and looked and its already gone as far as I can tell from my search in the For Sale section. Oh Well...I'll just keep waiting![&o]

Yeah he emailed me and said he had local offers. Its too bad because he was asking 100.00 less than retail.