Discussion Model Diesel Engines

[patmcc]

A mate of mine had an Alag X (?) 2.5cc in the late '50s. It had a very noisy squeak when turned over. He ran a couple of tankfuls through it then we used it in a combat type flying wing. It cut a few times at first but after probably something like 30 minutes accumulated run time it was noticeably more powerful & the compression/fuel mix adjustments easier to establish.
Once run in it was fitted to a profile Peacemaker. It proved to be about the equal of my AM25 & an Amco PB 35 but not as good as my AM35.

[Gluehand]

Originally Posted by patmcc

A mate of mine had an Alag X (?) 2.5cc in the late '50s.

It was most likely the 2.5cc X-3. An engine with good merits.
Here are my 1.5cc X-4 and 1cc X-5.
The X-5 is probably the most compact built 1cc that I've ever seen. It's TINY.

[RyanNX211]

http://www.modelaeroengines.com/us-s...s,Motor,Motors)

[RyanNX211]

http://www.ronald-valentine-engines....ollection.html

http://www.rojobcn.com/listmot_diesel.htm

[JohnAV8R]

Thanks RyanNX211. Yes, there are lots of interesting diesels from the past. I wonder how many got to fly? I can’t imagine someone actually taking a $2k Valentine 5 cylinder radial and flying it!
How about a few pics of your Webra in the Lancer?

[JohnAV8R]

Here is a little more information on diesel fuel.
UT video shows the run.

Model diesel runs on no ether.

http://video.google.ca/videosearch?q...d=0CBgQqwQwAA#


Norvel .15, zero ether fuel, Castor & Amsoil cetane booster

"the other guys" have a lot of information.

Forum information, no ether

RC Universe

http://www.rcuniverse.com/forum/forumid_87/tt.htm

[gkamysz]

If anyone has questions about diesel there are a few diesel guys who read the Engines forum regularly including myself. I happened to see this thread one day because it was recently replied to, otherwise I wouldn't have wandered into this forum.

Greg

[Gluehand]

It's been a little quiet here lately, so I thought a Frog Parade would cheer us up in the dark autumn...

L to R:

• Frog 50 Mk? with radial mount/backplate
• Frog 50 Mk?
• Frog 100 MkII
• Frog 100 MkIII
• Frog 250
• Frog 249BB earlier version
• Frog 249BB later version

Wondering:

• What differs the Frog 50 versions ? (mine seem to be the same)
• The "250" has an open lug....are there specialists, "fixing" such things..?
• The radial mount seen on the L/H "50": Is this a "commercial" accessory, or is it home made..?

Anyway, the old Frogs have their own personality, offering a serious flashback to the "golden years" of aeromodelling....

Cheers,

[Warren B]

Hi Gluehand
Nice Frogs, I like them too although some people seem to think poorly of them.
Currently I'm flying a nice 100 red head (like yours) in a 45" span Quaker and it goes really well, easy starting and lots of power.
I have the same 50 as you, a MkI.
The MkII introduced the rearward angled needle valve and a band of extra material around the lower crankcase which I think allowed a stronger conrod big end.
The MkIII looks the same as the MkII, but I believe has revised porting for more power.
I've not seen the radial mount, there were short tanks for the MkI and longer tanks for later ones.
My MkI starts easily and runs well, but not quite as much power as an ED 0.46 Baby and well down on a DC Dart.

[Applehoney]

The Mk.2 Frog 100 - third from left. The comparatively large exhaust port suggests it might be a Frog 180; my first engine in the '40's

[Gluehand]

Originally Posted by Applehoney

The Mk.2 Frog 100 - third from left. The comparatively large exhaust port suggests it might be a Frog 180; my first engine in the '40's

Oops! Applehoney, you may well be right there....it is really a bit bulky to be a 1 cc........result of a measure up will be posted here shortly....

[Gluehand]

Hello,
The engine was somewhat stiff, so this gave me a reason to clean off some old goo (even "preserving oils" thickens with time). The heat from a cigarette lighter was enough to loosen it up at the critical points before dismantling.

I have never used this engine in an aircraft, as I've always considered it a bit "fragile"......and cowardly choosen "another" engine when it's been time for final decision...

Identity confirmed:
My measurements of bore & stroke correspond exactly with the "100" specifications, so there's no doubt....it is the bulky, long-stroke Frog 100 MkII. The weight (on my scale) is 98 grams.

Below: The 1950 Aeromodeller article of this engine.

[Snorks]

What about the Frog Viper? were they any good?
cheers
Simon

Why did FROGs have the above mentioned reputation? Was is because they were the schoolboys choice of the day? Were they really any worse or that much different from the DC product? I have alot of engines- how ever I don't own a single FROG.

[vintage1]

My first engine was a frog 80, because it was the cheapest. I NEVER got it to run reliably.

Then I got a DC bantam glo. It always ran, but it was gutless. Then I started acquiring other boys stuff that they didn't want or couldn't start. pee wee, babe bees, various diesels. Isatarted them all no problem.

Even the Frog 149. Beautiful engine. I think that 80 must have simply been really stiff, and needed an hours bench running.

Best diesel was the PAW 19D, of what we had. worst was the Frog 80. Ended up with the Frog 149, Amco 35 (good once started, but a finger ripper to start) ME something..1 or 1.5cc reliable but gutless.

Never could afford a Mills. or a DC dart. Did most flying with the little COX glo engines. reliable, easy to start.

Only ones I'd fly today of that lot would be the Frog 149 and the PAW 19.

Really, removing the rose tinted spectacles, most diesels of that period were pretty BAD. Very poor tolerances, heavy castings weak in places.. the odd motor from the odd manufacturer stood out as a lucky design. I believe the Mills 75 was one, the DC dart another. And that Frog Vibramatic 149. Only premium manufacturers like PAW or Oliver Tiger turned out quality products across the range. And a few others of foreign design'

Other units could if you spent as much on fuel to run them in, or tinkered with carbs and parts, get there in the end, but who needs that when you are a 13 year old on a very small budget?

It was essentially Cox, with their precision automatic lathes, that started turning out far more reliable and powerful engines as silly prices, that got the ball moving for me.

[Gluehand]

As I understand/recall, the later "ball bearing Frogs", i.e. Viper and the 2.49BB's, were fairly well received by the press, and in general positively thought of....however I doubt that the sales figures were that impressive....
Maybe these upgrades came too late....these were the years when diesels gradually left the scene, and many of the "traditional" manufacturers struggled.

Apart from these top-of-the-line-Frogs, the previous models were "honest" sport engines. No powerhouses, but yet the quality couldn't be complained on....a decent "schoolboy's choice" like Simon says....
Frogs were rarely seen on competition result lists, so they lacked that gleam that would have helped them moving up from the pure "sport" epithet...

Designwise, they have a personality of their own, and today the Frogs are obvious symbols of the "golden years".....and that logotype is just wonderful...