ESE's works engine tuner

[adegnes]

Or create a pool of petrol and resting in it a wick you could raise or lower in the airstream.

Whoops, wrong century.

[andreas]

First up, sorry for it being sooo long since my last post.
My YouTube channel kinda blew up and I'm having a hard time keeping up with just the mails, messages etc.
I know there's a few pm's I haven't gotten to here also.

With my limited experience in diy plating most epoxies, suitable for cylinder work or not, would survive a strip+replate pretty well.

Anyways.
Currently at the airport in Denver Colorado, on my way back from my first attempt at racing at Bonneville Speedway(event got canceled, rain)
We had a great time regardless, and now I have time to build a proper engine with my 100% width exhaust port cylinder on it.
Going to run on nitromethanol, efi, throttle slide part of the rotary valve cover.
Variator transmission electronically controlled.
Need to read up on the do's and don'ts with fuel injection.

A747 is genius on piston wear but I have some concerns about it's bearing properties. Might be nonsense, but to see your big end give in I thought I'd mention it.

[ken seeber]

With my one rpm constant load engine and a small carb taking care of of everything except WOT, efi could be REALLY simple couldn't it?
Just one injector in the intake duct, duty cycle controlled by temperature and air density.
No timing or anything.

Here's what some guy in Oz did (with success ?) ages ago. It is a 125 cc BSA Bantam. From memory, the 2 carbs opened simultaneously rather than being staged.

[lohring]

Model engines running high nitro fuels have run a simple "injection"system for years. Pipe pressure is fed to a sealed tank. Often we run a hopper tank that's always full to offset the effects of fuel sloshing, especially in high G turns and rough water. The output from the tank runs through a flow valve. This valve can be radio controlled to adjust the mixture on the fly. We mostly run either at idle or wide open so subtle flow control isn't needed. Some "carbs" have a low speed adjustment to help. As the power goes up the pipe pressure rises, delivering more fuel. The methanol based fuels aren't very mixture sensitive, especially on the rich side.

Lohring Miller

Tank & pressure line


Remote flow valve

[Frits Overmars]

Model engines running high nitro fuels have run a simple "injection"system for years. Pipe pressure is fed to a sealed tank. Often we run a hopper tank that's always full to offset the effects of fuel sloshing, especially in high G turns and rough water. The output from the tank runs through a flow valve. This valve can be radio controlled to adjust the mixture on the fly.

We use the same system for F3D model pylon race planes. These don't use nitro at all (forbidden), just 80% methanol and 20% (yes, that greasy!) oil.
The fuel is contained in a bladder in the tank. Exhaust pipe pressure administered between the tank and bladder walls squeezes the fuel from the bladder to the inlet.

There have been experiments with radio-controlled needle jets, but more than one pilot had to regret his greed when he tried to squeeze the last couple of revs out of the engine and was punished with detonation that blew his glow plug away.

This system is quite sensitive to the tank position, as the centrifugal force in the corners can strongly influence the fuel flow. Measuring the magnitude of this centrifugal force failed because the g-force sensors that we used, couldn't register more than 36 g...

[Flettner]

This system is quite sensitive to the tank position, as the centrifugal force in the corners can strongly influence the fuel flow. Measuring the magnitude of this centrifugal force failed because the g-force sensors that we used, couldn't register more than 36 g...[/QUOTE]

Hahaha Wow.

[Frits Overmars]

This system is quite sensitive to the tank position, as the centrifugal force in the corners can strongly influence the fuel flow. Measuring the magnitude of this centrifugal force failed because the g-force sensors that we used, couldn't register more than 36 g...

Hahaha Wow.

Which makes me wonder: what kind of g-forces can an autogiro generate? I suppose you won't need to wear a g-suit..

[lohring]

Even slower model boats I've data logged can pull close to 4 Gs in the turns with +- 1 G vertical accelerations even in smooth water. I bet high performance model boats pull closer to double that from my experiences with bent turn fins. Frits, you hit on the problem with radio controlled valves. However, unlike airplanes, boats don't run under load until they're launched. That makes it harder to find the right needle setting.

Lohring Miller

[Frits Overmars]

... unlike airplanes, boats don't run under load until they're launched.

That would call for something like a tuning bucket, wouldn't it?
However, I'm not sure that immersing the boat propeller in some basin would sufficiently imitate track conditions, as playing with airplanes taught me that the propeller is somewhat unloaded when the plane comes up to speed. You can hear it in the video below: the engine is running WOT all the time, but the plane needs about a full lap for the revs to build up and stabilize.
http://www.youtube.com/watch?v=5aBCQGq5Al4

[F5 Dave]

Geez they don't rev very high do they?

It also strikes me as um, potentially somewhat dangerous?

[adegnes]

You wouldn't want the pilot suddenly realizing you slept with his wife!

[teriks]

Geez they don't rev very high do they?

It also strikes me as um, potentially somewhat dangerous?

Saw 34krpm on the logger at the wc this year. Surprised the rod stayed in one piece.
Prefer to peak close to 33krpm so "geared up" with a heavier prop.

[husaberg]

Saw 34krpm on the logger at the wc this year. Surprised the rod stayed in one piece.
Prefer to peak close to 33krpm so "geared up" with a heavier prop.

I assume they just run plain bronze bushed big and little ends, is that right?

[peewee]

Attachment 343016 Attachment 343017 Attachment 343018

These are hardened steel washers from a Suzuki RGV250. 0,010" side clearance (0,254mm). Very close slip fit on the pin and no appreciable grooving of the pin after hours of service. These washers are used to centralize the rod when no big end washers are being used. I have seen steel and hard anodized aluminium in Yamaha KT100 cart engines. I was not that impressed with the life of the alloy KT100 ones. I would think washers made out of any good quality steel would be fine. I don't think hardening would be all that necessary for a short run competition engine.

eh mate i got around to making the washers. ctankshaft and lower rod still have a bit of side float but atleast the small bearing wont be able to walk around off center as much.

[Frits Overmars]

Geez they don't rev very high do they? It also strikes me as um, potentially somewhat dangerous?

You wouldn't want the pilot suddenly realizing you slept with his wife!

Dave, you're right: they don't rev very high. Maximum power comes at around 32.000 rpm and maximum revs are around 35.000 rpm, which, with a 19 mm stroke, works out at a mean piston speed of 22,2 m/s. If these little screamers were to equal the piston speed of an Aprilia RSA with 54,5 mm stroke and 14.500 max.rpm, they ought to rev to 41.600 rpm. Imagine what that would sound like.

Dangerous? Noticed the guy wearing the white ear protectors in the video? That's me, staying close to the pilot, which is definitely the safest place.
Those F3D pilots are supposed to fly around three pylons and they don't want to lose time making detours, so sometimes they cut corners, literally.