Matador

[Danny Fenton]

LOL Chris have you lost the plan for the fus? Savoring the dope is the "pudding" not the main course.... I don't know.... I can hear the Keil Kraft thwackers on their way to you, and they aren't singing carols

[Pete B]

Just to whet your appetite, Chris (if it needs whetting!) here is a very dated piccy of my f/f Matador, with a shiny new Frog 150, built back in about 1967, when I knew very little about trimming............I'm sure yours will have a much longer career!!

Pete

 

[Chris Bott - Moderator]

Ooh thanks Pete.

I'm building mine as a replica of my first ever R/C model.

Trouble is, I don't have a photo of it

[Big Bandit]

Looking OK for the wing Chris, still not had the Nylon from SMC, apparently Flair are having delays. I'm in Leeds tomorrow so I hope Sherwoods have some. I must admit to looking forward to the smell of dope again. Good buy with the Frog.

 

Cheers,

 

Chris.

[Steve Hargreaves - Moderator]

Lovely little engine that Frog Chris...it looks brand new....I have a 1cc version (Frog 100?) in my Mini Tyro & its a great little engine.......a bit prone to the compression lever unscrewing in flight & stopping the engine however..... I added a locking lever so I could "lock" the compression screw which cured the problem.

 

I had a DC Sabre (1.5cc) in my Matty (circa 1978) & it flew it OK as I recall but was a little bit marginal when the wind blew. Mind you mine had a fully sheeted fuselage (1/16th balsa) & possibly a sheeted LE too (can't really remember) to make it stonger for radio control & this plus the weighty gear of the period will certainly have pushed the flying weight up.....mine was covered in heavyweight yellow tissue & sprayed by a mate who had just got an airbrush & compressor.....as you can see he went a bit overboard but Hey!! this was the 70's

 

[Chris Bott - Moderator]

Hi Steve, yes the blue headed Frog does seem to be in very good condition. I was all for giving it a good flicking yesterday, but of course at that moment the rain came down and carried on for hours.

 

The Frog 100 red top was the engine I'd had in my first Matador so it was a toss up between one of those or the 150 that I'd always wanted. The 150 came up for sale so that was that.

 

What prop would you use on the 150? Any idea?

 

PS - Love the outfit, but I don't think I'll be going for that look at the fly in!

 

[Chris Bott - Moderator]

Here is the ED Hornet running by the way, this is my other possible power source for the Matador.

 

It took far to long to get going to show the whole starting sequence. I had to add a remote needle valve to get it to run smoothly.

 

 

Edited By Chris Bott on 05/12/2011 20:57:29

[PatMc]

Hi Chris, my Hornet runs no problem with the normally positioned needle valve. When I got it it didn't have an induction tube or spray bar so I made one using brass tube & a "universal spray bar" (IIRC they were made by MS) I soldered the spray bar in position to avoid any air leak or the fuel hole in it the being moved inadvertently when in use.

 

The Frog looks to be a good buy, I think it will be a lot more powerful than the Hornet & IMO a better bet for the Matador. I you care to send me a PM with your email I'll send you a PDF copy of the Frog 150 MkIII instruction manual.

[Chris Bott - Moderator]

Thanks Pat PM will be sent straight after this post.

 

Yes I think the "normal" needle valve was all wrong when I got the engine, it has a washer soldered to the spraybar and then it is held in to the induction tube with a nut on the far side.I think there was a lot of air leakage.

At this point I tried the remote needle, which proved the engine its self is OK.

 

Since then I've done a little more:

With the air sealed off temporarily with a couple of slivers of fuel tube as gaskets, then I found the fuel could not be shut off enough. So I moved the collar along the needle a little.

This is starting to work well, but now the needle collar is so far out that the setting wanders all over the place.

I'm sure I can get it sorted by spending a little more time.

But then the Frog turned up

[PatMc]

Hi Chris, Email sent.

 

IIRC the ED Bee (both versions) & the Hornet came with the needle valve soldered to the induction tube when new.

[Chris Bott - Moderator]

Instructions received with many thanks Pat.

 

Yes I'm sure you're right. I may try soldering. Although I have a feeling the induction tube in mine looks suspiciously like aluminium, so could have been a replacement at some point?

 

I'm a little surprised that the Frog instructions suggest such small props.

8"x6" for sport flying, 7"x4" for stunt and 7"x4" cut down to 6 3/4" for Team race.

I have an 8x6 nylon Taipan which will do nicely.

 

If you look at the photo of the Frog, you'll see the starter cam is missing. Do I really need this? (The spring seems in very good condition indeed).

I seem to remember happily starting the one in my youth just by flicking.

Does anyone have any idea where I might source one?

 

 

[PatMc]

 

IIRC I used to use an 8x4 or 8x6 with the 149 Vibromatic for c/l & later RC. I think the 150 MkIII peaks at higher rpm but has more torque throughout it's range anyway so the same size props should give more power.

I always found the starter cam & spring to be a gimmicky nuisance. I suspect the only reason the spring is still on yours is because the prop driver has to be removed first to get it off. If the driver has a tapered fit as shown in the instructions it should be easy to remove by dipping the front of the engine in boiling water then gently tapping the back of the driver in a few places. If it's on a splined shaft it might not be worth the risk of damaging the driver.

[Chris Bott - Moderator]

I think you're right again PatMc. I think I'll leave it in situ. I may just have to trim the rear of the Taipan to clear it though. This prop just happens to be unusually deep right at that point.

[Steve Hargreaves - Moderator]

Hi Chris....all is authentic 1978 flying gear & I commend "the look" to you for that true vintage atmosphere.....

 

My little Frog has a greeny-gold head but I'm pretty sure it's a 100.....it has an 8x4 on it in the Mini Tyro.

 

For your 150 I would be tempted by a 9x4 prop....I always like big diameter props on diesels as the flywheel action makes them easier to start....plus it keeps the revs/noise down & the thrust up....I certainly wouldn't go below 8".....a 1.5cc diesel on a 7" prop will be a nasty little finger biter....

[Chris Bott - Moderator]

mmmm good point. Thanks Steve.

I have a red tipped Top flight prop at home, that may be a 9". Can't look at the moment though

[Chris Bott - Moderator]

Managed to spend a little time with the covering.

 

If anyone want's me to recommend using nylon, - I wont!

I had some sort of rose tinted recollection of how this material goes on. But now I fully understand why I left it behind. Most of my building techniques have moved on a long way since mt early teens. I don't think nylon covering has improved whatsoever.

 

So, from now on, I'm claiming that I'm trying to recreate the model I built as a 14 yr old - exactly. To that end - it looks like it's been built by a 14 yr old. (which may be an insult to todays 14 yr olds, sorry about that)

 

The bottom is looking very tatty so let's move along...

The technique for the top was to iron the creases out of the nylon, then soak it on water and wring out. Allow it to expand while doping the outside of the structure, then flop it on and keep pulling until it was reasonably tight and finally brush more dope through the edges.

 

After it's all dry, the edges are pulled around and doped underneath before a final trimming.

Subsequent coats of dope seem to have had different effects. Some even seem to have highlighted the little creases at the same time as generally shrinking the fabric.

So, we have a wing. All nice and tight as a drum, all nice and straight and tough as old boots. But the sheen is uneven and plenty off little creasettes still show. I think in a crash, I will at least only have to pick up one nylon bag of balsa.

 

When I cover the rest I'll try it with the nylon dry. That at least will save screwing it up to squeeze the water out.

I'm still having trouble with getting all the edges to stick down too, a dab of dope to stick anything down has the potential to unstick something new at the same time! I may end up with the odd last edge stuck down with cyano.

 

With a bit of diesel fuel smeared over it, it will look like I've just taken my original out of the loft . Mmmm that sounds a better story than owning up to building it! Don't tell anyone.

 

 

[Big Bandit]

Hi Chris,

 

I had problems with covering the tailplane on mine, but now I'm getting into it I'm enjoying it. Like you it was getting the edges stuck down, on the fus I've coated the outer frame with full strength then wicked thinners through to reactivate the dope underneath and it seems to work much better.

 

When I cut the covering from the centre section of the tailplane. the finish on the inside was very good, so when I've got a coat on the fus under side, I've turned it over again to allow the dope to dry on the surface rather than inside the airframe so should get a much more consistent finish and probably lighter too.

 

Cheers,

 

Chris.

[Chris Bott - Moderator]

mmm that all sounds a good idea Chris.

Except maybe when I pin the wing down to keep it straight while drying...

 

I think maybe I should have started the covering with something smaller to get some practice.

[Chris Bott - Moderator]

Decided to try the Frog 150 today and could do with a little advice.

 

I cut my finger second flick so the prop is suitably blooded. Then I probably lost any kudos thus gained by switching to a file handle. Just while the finger heals of course.

 

It started pretty quickly, say about 10th flick, and a few adjustments later was running fairly sweetly.

 

Next, I must have put a curse on it by getting the video camera out. The result is below.

Questions for the diesel experts:-

Is this fairly typical for starting a Diesel?

How should I improve my technique?

It seems to vary in revs just a little, any ideas why?

When I shut off the air at the end, it managed to carry on for quite a while, where might I look for an air leak?

 

[Bob Cotsford]

Chris, I don't know about the Frog, but a lot of engines used sub-piston induction - ie the bottom of the piston clears the bottom of the exhaust port at tdc. That's one possible source of your air leak, I seem to remember closing the needle to stop them. The next most likely leak is a loose backplate, then a worn front bush (is there any play in the crank?).

I seem to remember increasing compression a tad to start them from cold, or giving a small prime through the exhaust port.

I think my skin must be much thinner than it was when I was a teenager, I daren't try to flick a motor over without a chicken stick these days.

[Chris Bott - Moderator]

Thanks Bob I'll have a look at those things in the daylight.

Alas I think you may be right about the thinner skin. I'll be checking the prop for sharp bits too though.

The finger over the intake to suck for a prime seemed to be enough. But yes I remember a quick squirt in the exhaust now you mention it.

 

One other thing:- A couple of times it started in reverse. Is this a problem? It didn't run like this for more than a second or two.

[Steve Hargreaves - Moderator]

Bob is right about sub port induction but I don't think it would be enough to keep the engine going with a finger over the intake. I would expect it to stop pretty well instantaneously so I think you may have an air leak somewhere....as Bob says the backplate would be the first place to look.

 

I had a look at my Frog 100 & that certainly has sub piston induction....I would guess the 150 does too...take a look through the exhaust port with the engine at TDC....if you can see daylight then thats sub piston induction!!!

 

My thoughts on what I saw on the video are as follows (for what they are worth....!!)

 

First off it all looked pretty good to me....the motor seemed to sing quite sweetly once it was running....I think you will find a bit of variation in the revs so I wouldn't worry about that....

 

What size prop do you have on it Chris...? Looks about 8" to me....I'd be tempted to try a 9x4 or similar...it will keep the revs down a bit too....A bigger prop really does help stop the little blighters biting back....I have an 8x4 on my 100 & your engine is 50% bigger so it will easily swing a 9" prop. Probably a 10" if you wanted but that might be a bit silly!! Also I tend to find that my Frog likes to be pretty wet for starting....I fill the intake with fuel twice & back off the compression a bit to start mine...effectively I make up the compression with extra fuel!!!!

 

Another thing to watch is the compression screw backing off when the engine is running.....mine had a habit of doing that & stopping but a locking bar sorted that out. The compression screw is probably 2BA....I think I have a tap somewhere if you need it....

 

The starting backwards is quite common....especially if the prop is a bit small (see above)

 

I think a lot of it is just technique....you just need to get to know each other!!!!

[Chris Bott - Moderator]

It's worth a lot thanks Steve.

 

The prop is a spiteful 8x6. I have dug out my red tipped Top Flite and that just happens to be a 9x4. So I'll have a go with that if I can successfully sleeve the (too large at the moment) hole in the hub.

 

You're right it likes to be wet, no sign of firing at all until there's a good slurping noise from the cylinder. Then of course you're not far off a hydraulic lock or the firing backwards just as you're pushing over the top.

 

I'll have a watch of the compression screw. I have some 2BA nuts I could solder to a lever. I may even have a tap, there was a selection when we cleared out my Dad's garage.

 

PS

I think you're absolutely right, I think the Frog and I will be fine after a few more dates.

 

 

 

[Big Bandit]

Hi Chris,

 

Fitting the prop so it comes to compression when at the ten past six position helps. If the back plates leaking a thick brown paper gasket works very well.

 

Cheers,

 

Chris.

[Steve Hargreaves - Moderator]

Posted by Chris Bott on 21/12/2011 23:10:07:

 

PS

I think you're absolutely right, I think the Frog and I will be fine after a few more dates.

 

 

 

Be careful.....if you accidentally kiss the engine (whilst blowing through the exhaust ports to clear some fuel perhaps!!) you might turn into a Princess.....

 

Have to say I'm impressed with that little Frog....I guessed it would be an 8x4 you were using so to hear it spinning an 8x6 at such a speed is impressive.....I was thinking a 9x4 might take the edge off but from its performance on the 8x6 it will probably spin a 9x4 at a similar speed (the bigger diameter will still help with starting so definitely worth using a 9" prop) My concern is that a 6" pitch might pull the model along a bit too fast but would certainly be worth trying.....maybe a 9x5 from here might be worth a try.....hardly Vintage but Hey! at 8,000 rpm who will notice.

 

On these single speed engines prop/pitch selection is the only thing you have to control the model speed so worth experimenting....

 

Amazing what these little diesels will do isn't it....I have a 9x6 on my OS25......