Topic: Engine mounting on a c2000 model.

Hi all, Just a quick question about engine mounting orientation.
I notice in club 2000 some engines are
Mounted vertically upright and on some models
The engine is "canted" or mounted at 45 degrees
To the vertical. What's the advantage of mounting
The motor on an angle? I built a wasp and the photos show both set-up's so what's better?
Brgds
Dave

Hi Dave

It's bene a while since i built a C2k model, but IIRC the reason for mounting on the 45 is to do with better fuel pick up

cheers

Duncan

Ok duncan, the lower carb towards tank centreline I get, but is this not offset by turning the engine and increasing the models frontal area ( I.e the silencer
Is no longer covering the wing leading edge and engine is sticking out the side of fuz into breeze) discuss!
I really don't know the answer but it's worth a debate, ok maybe not!
Cheers
dave

Hey mate

I think it is worth a debate! Some guys have it 90 to the side with the muffler right under the model as well. Don't know the reasoning.

I have a model which I will finish one day which has the cylinder at around 8 o'clock. Reasoning is to have the motor mounted quite high on the firewall so that the thrustline is closer to the wing. The orientation is so that the max amount of the head is inside the firewall footprint, whilst keeping all the airflow to the wing clean.

Will it land without cartwheeling, or will the above be any benefit at all? Who knows! Will find out sometime! Probably all the above benefits possible with an upright engine and a low wing! - with none of the drawbacks.

Z

I think it might be as Duncan says but also related to the fact that the model will spend most of it's time in partial knife edge which will, in effect, put the engine in the upright position for most of the flight.

Stu

Hi Dave,

I have found the following works best.
Mount your motor at 90° with the spray bar level with the centre of the tank. (this is the closest to neither gravity feed nor suction and equilibrium using just exhaust pressure.) yes the needle setting at the start is gravity fedd and the end of the tank will be suction. In a race you will not use a full tank therefore the change is not as dramatic as full tank emptying.
Try to mount your tank flat so that the head change of the fuel level is less through the run.
Use a fixed pick up, I have this only 1/4" or more away from the back / bottom of the tank  as this shortens the pick up point to carb, Less distance to travel is allways better, but remember this when fuelling up as you may not get a full fill.

This all might sound obvious stuff, but makes a massive difference to performance. I would rather have a motor run well for 10 laps than a cleaner frontal area and motor coughing on lap 7!

Before anyone tells me I'm wrong here due to pylon models spending time on there sides. Remember the fuel is often forced to bottom of the tank as if it was lying flat on the ground due to the forces exherted in a circuit. Infact if anyone thinks the fuel just goes to back needs to fit a camera to there model. It spends as much time at the front hence front feed combat tanks in the 80's

If you want to mount the tank in any other way try a bladder tank!

Oh be warned, all of the above is all opinion!!

the opinion of the fastest pilot in C2k though, so worth listening to

the opinion of the fastest pilot in C2k though, so worth listening to

And learnt from FASTER flyers over the years!

And just in case you don't already figure it out from Duncan's post - he's also far too modest!

Z

So...... just to clarify, is it best to just have a length of brass tube, bent to the angle needed to get a pickup from the tanks bottom rather than any kind of clunk? And, front bottom of tank, or rear bottom? I'm guessing rear, but want to be sure.

Guys, thanks for all you advice. Unfortunately
FLAPPY is my competition up here in Scotland so I'm now running scared.
Brgds
Dave

Before anyone tells me I'm wrong here due to pylon models spending time on there sides. Remember the fuel is often forced to bottom of the tank as if it was lying flat on the ground due to the forces exherted in a circuit. Infact if anyone thinks the fuel just goes to back needs to fit a camera to there model. It spends as much time at the front hence front feed combat tanks in the 80's

Makes perfect sense to me mate, the only time the fuel would be at the back of the tank is when the model is accelerating.  The position of the fuel in the tank is always going to be a reaction to the force applied to the model.   Therefore if a model is making a high g turn on its side towards its canopy then the fuel is going to be on the bottom of the tank.  If you do manage any levelish flight between the pins then gravity is going to be dominant so the fuel is going to be at the bottom of the tank just the same.  So the best pickup will be a fixed one towards the bottom of the tank.

CM

Thanks to all the guys who PM'd me the 'real' info, so that David Kelly didn't see it 

Thanks to all the guys who PM'd me the 'real' info, so that David Kelly didn't see it 

Brilliant 

Oooh that's low, ok Tony I'm looking forward
To march 24th's race more and more!

Hahaha..... me too mate, cant wait. Hopefully we can oust the current club champion from his perch.