Diesel stunt interest?

HI John,

I've been playing with a PAW .09 on a Sig Akromaster. It's really a nice combination. I've been flying on 52' lines and using a 9-5 APC prop. The airplane was nose heavy and I just made some minor changes and haven't had time to fly it yet. Even with the noseheavy condition I could still fly the entire pattern with it and the only bad parts are the overhead maneuvers.

I'm building a Sig Banshee and will power it with a PAW .19. I will move the the wing forward about 2" and add adjustable leadouts. If this is a good combination I intend to move on to a .60 size ship with a PAW .40.

The nice thing about my little Akromaster set up is that engine speed is constant and best of all, it isn't tank sensitive like glow engines.

Randy Ryan

Diesels are somewhat more individualistic that Glo engines I think. One will start and run on the flying settings; another you'll have to increase compression to start it, and with the two PAW's I've run on the bench, you have to decrease compression to start. Once you have flown a particular engine a number of times you'll understand it about as well as any glo engine. The more time a diesel has on it the better it starts and runs.

I handle the fuel like I do glo fuel, I fill with a black squeeze bulb and put the cap back on. I've used 15-year old fuel with no problem. The idea of making a filler cap for your fuel can so you don't ever open the can on the field is a good idea, however. You can't use silicone tubing. Fuel economy is better than glo, varies with engine. Prop varies with the engine, maybe larger than with glo, maybe not. (Randy, the instructions with my older model PAW 09 specifically say not to run a large prop. Try a 7 x 6 or a 7 x 4, you'll be pleasantly surprised.)

In general, once I get a needle setting, I leave it alone. My experience is that diesels are as sensitive as glo engines to tank position. With a familiar engine, I set the compression where it is supposed to be and the engine can warm up while I'm walking out to the handle. This may not work with larger diesels. Generally diesels run a steady speed. My Tigres, however, pick up considerable RPM when launched. I'm overpropping them, I'm sure. Probably they would really like an 8 x 4. They also wind up a little in high wind. They were designed to be a high RPM engine.

I have a Tower 40 with an RJL diesel head. On the bench it turns a Zinger 13 x 5 at 9,200 set a little undercompressed and a little rich. That's the cheapest 40-size diesel I know of.

I use Davis diesel fuel, mostly his 1/2A fuel in the older engines. I understand Aerodyne and Eric Clutton fuels are good.

I'm happy to talk diesels any where any time. My email is [email protected].

Jim;

I am curious as to how well this engine has run and how satisifed you are with it. Also, what size airplane are you running it on?

I have the idea, tested a little bit, that diesels run better on flexable propellers, like the white Tornados, than they do on similar stiff props.

By the By, Aeromodeller is publishing a three-part series on a visit to the PAW factory. Fascinating! The article gives their web site as www.paw.ac

ether
kerosene (paraffin in the UK)
castor oil

plus an ignition improver such as amyl nitrate or isopropyl nitrate

The Kerosene provided the bulk of the 'urge' in the fuel though too low an ether content can make starting difficult.

From other message boards I gather that getting ether in the USA can be difficult and that aerosol cans of an ether ignition helper have been used with various degrees of success.

Here are the commercial formulations used by a UK fuel mixer (model Technics)

The DS1000 is for running in and general sports flying, the DS2000 is fine for plain bearing diesels and the DS3000 is for ball raced engines and is regared as a performance fuel, not recommended fopr plain bearing engines due to the lower castor content..

The kerosene provided the 'urge'

Ether Kerosene Castor oil Isopropyl Nitrate

D1000 35% 35.00% 28% 2.00%

D2000 30% 43.75% 24% 2.25%

D3000 30% 47.50% 20% 2.50%

PAW the company have recommended the use of Model technics fuels in the past.

I think that Eric Clutton, a UK ex-pat in the USA can supply diesel fuel ready mixed.

I have found that it is no cheaper to mix my own than to buy ready mixed fuel though I will be tinkering with formulatons when I have a go at vintage team racing next year.

The palns are available from the Aeromedeller website at http://www.modelflying.co.uk

Hi Peter,

My Akromaster was built stone stock. It was merely a testbed that turned into a pleasent surprise. If I were building another I'd shorten the nose an inch or so, or maybe move the wing forward by that amount, the tail moment is on the short side. I'd add adjustable leadouts and a tip weight box too.

It's true that the larger diesels seem to be shakers to some extent, but the smaller ones are just as smooth as their glow counterparts in my opinion. I wouldn't pass a harsh judgement on them though, especially the newer ones. I've yet to buy my PAW .40, but I'm not overly concerned that it'll be any worse then any of the old iron piston glow engines I use now.

the bronze bushed engines are from the combat engine range and are ported differently to allow the engines to develop more revs.

There is also a chromed bore version of the combat range which costs considerably more and is aimed at those who want to wring out every last drop of perormance. The chromed engines do not appear on the PAW web site tho' the prices can be seen at http://www.justengines.unseen.org

I outlined my diesel experience above. I'm building twin and single engine versions ot the Trixter A-B. The single will have one of my trusty Tigre diesels on it; however, the twin will have two Cameron 19 Glo's (the engine I learned to fly CL with in 1953.) You see what I'm saying?

Keeping diesel fuel cool and being obsessive about keeping it contained are very good practices. I'm not that obsessive but it works for me. However, I recommend you start out being obsessive and then see if you can get away with being more relaxed, if you so desire.

I too fly Diesels and enjoy them very much ! They are a different breed of animal though inwhich time and effort in learning them is a must! I have mounted a PAW TBR .19 on a SIG AkroMaster .15 sized plane and a PAW TBR .35 on a Sterling RingMaster .35 sized plane. I have flown both models ALOT, and have learned ALOT. Yes, both are very nose heavy, but with added weight ( yes, ok alot of added weight) the will both fly pattern. Why did I do this plane/engine combo ? There is reason for this. I wanted to see if diesels were for me, so I switched a couple of the already built glow powered models I have over to be diesel powered models.

Once I started a diesel up and realized the potential, I knew they were for me. Lots of torque, steady RPM's throughout stunts, and something different than the same old glow engines I've always had. I just recently bought a PAW TBR .09 w/muff for C/L and I'm planning on building a Brodak's Lightning Streak Jr for it. Prior to thinking of this combo I didn't know but, Brodak's shows the plans of the Lightning Streak Jr. powered with a PAW .09 on it!

About fuel, yes Eric Clutton sells premixed fuel which I believe so far is the best from which I have tried.

Also, about bearing or bushing choice of engines, I always buy ball bearing engines. They feel smoother and have more power. I believe PAW even indicates up to 1000 RPM gain over bushed ones.

My couple of dollars worth.....

As I posted above, I'm planning on mounting a new TBR .09 I bought on a Brodak's Lightning Streak Jr., does it really need a .15 ? Didn't your L.S. turn out WAY nose heavy ?

If it turns Tree Trunks as props, it's gotta be a Diesel !

Dmacsimum Speed Limit.

Right from the unflapped era (APS Ambassador, Blue Pants, Harlequin, Mercury New Junior Monitor for Elfin 2.49, AM25, ED Racer and so on) through mid-sized flapped stunters (Mercury Monarch, Keil Kraft Spectre, APS Scimitar) to relatively large models (APS Thunderbolt, Skua and Skiffler - all around 48" span and for AM35/Rivers 3.5 or Oliver Tiger Major) and onto 'full size' stunters (Tony Eifflander's Freebird for PAW 35).

Although I must say that whilst designed for diesels most of the examples of the above I remember from the late 60's were actually glow powered (I recollect Merco 29's being used in the Scimitar and Thunderbolt).

Just Engines also currently have a diesel version of their 'cheap' Leo 46 available which is apparently 'mildly ported' and might be worth a look at!

Oh how I wished I still had all of the control line stuff I'd ever owned!

As Steve said, I was going to reply by saying:

"I think diesels stink!"

But that's not the right way to say it. It is not the technology that has that pugnatious odor; it is the fuel. The biggest problem with diesels, besides the smell, are 1 - weight, 2 - (sometimes) starting problems, and 3 - the setting problems involving a needle AND a compression screw, along with the need to properly warm up the engine (30 seconds or so) before establishing the final setting.

They have a more constant, low rpm run, somewhat like the 4-cycle engines, and share with them the fuel economy and the ability to turn a larger prop. They, also, share the fact, that with a more constant run, there is no, or certainly less of a boost up on top, which can result in a lighter than necessary line tension overhead.

All that said, however, any engine that can turn a larger prop (4-cycles included) can't be all bad. Again, in Europe and other areas with their lack of availability or high priced nitro, diesel technology has proven itself in stunt circues.

And then, of course, there are these unreasonable contest directors who unwaveringly refuse to carve a groove in the runway so you can have prop clearance for your 14 inch prop on take off. Maybe we can have a recount here. Appeal to the AMA to overturn their decision, bring in our own channel cutter to give prop clearance, ask for a separate runway so our plane will have prop clearance for take off, maybe allow for a hand launch if our plane doesn't have sufficient prop clearance, see if we can extend the contest dates if our request isn't complied with, hand signs and start a protest with the other contests who agree with our request, cry and whine with the media....

For example:

One must fiddle with compression and needle. I set the needle and leave it alone for many flights. On my Super Racer I do not fiddle with either compression or needle.

Diesels must have a warm up period. Not so. Crank the compression over to where it is supposed to be and go fly. Caviat, this may not be true for large diesels. Works for ST and ED 15 size.

Diesels only swing large props. The two older plain bearing PAW's I have caution that running large props will excessively strain the engine. According to Aeromodeller review, my ST G20-15 diesel peaks at 18,000, that takes a 7x4 rather than the 9x4 I run. and that is why it really picks up on takeoff and winds up a little in maneuvers (OK by me on small engines.) Many of the more modern diesels are high-RPM engines.

So don't let your diesel thinking get in a box.

Who needs a trough..just use bigger wheels

I picked up th Baby Stuka plan some time ago from Leonard and have yet to cut a rib for it. It is a pretty little thing and I was thinking about a 1.0cc with 3-blade.

I know there was a lot of interest in das "Li"l Stuka" but haven't heard of anyone building and flying one yet. I'd love to hear some "War Stories" on this model.

My original thought was an .09 but after seeing the plan, it looks like a strong .049 (Diesel) might fly it. A 1.0cc would give me a little more confidence. I have a MP-Jets .061 diesel but it might be a little too strong. I do like the muffler to keep the exhaust off.

I know an .049 will fly small models like this and it is usually done on fairly short lines. I like a little more space for maneuvers and appreciate a little line tension.

Dan

Most US modelers are unfamiliar with diesels in the first place, so any diesel faces overcoming that unfamiliarity. With a conversion there is an additional layer of uncertainty. You don't see many posts saying "I can't get my PAW, or ED Racer, or whatever, to run." but you do see a fair number of posts saying, "I don't like my Davis conversion." So a conversion is snakebit twice.

What you are asking a stunt flyer to do is to take an engine that he understands and is reasonably happpy with, and spend a fair amount of money to convert it to something he does not understand and has heard mixed reviews about.

You might say but what about the pipe? Pipe technology was well developed, proven, and widely accepted in other events before it was ever tried in stunt.

I've never seen a conversion engine, rather than my own, run. Bob Davis has stayed in business but he hasn't made much impact on model aviation in my part of the USA.

I'm not disagreeing with you. I think diesels have a lot of possibilities in stunt and that there are a lot of old wives' tales circulating.