Future Topics

[carey shurley]

This is a current list of planned threads in no particular order

• Preventative Maintenance
• Oil
• Build Threads
  • TSA Infusion 700G
• Engine Related Reviews
  • OS Max GT15
• Mixture Settings
• Wiring considerations for Gas Helicopters

[*]Operating the OS Max GT15[*]600 vs 700 - Which one do I want?[*]Break-In procedures[*]Intake system performance impacts[*]Exhaust system performance impacts[*]Fuel Topics[/LIST]

[klamp]

I'd love to see a topic on carbs. With as little information about gas helis as is out there, info on carbs is even slimmer. I had a hell of a time picking one with my 290RC. It came stock with the WT990, but I could find little info about it and none specific to helis. I finally went with the WT664 since that was the one I could find the most info for in helis and also what a Zenoah rep recommended for a heli application.

I still don't know the difference between jetted and non and which is the better choice for helis.

[sps3172]

Hi Carey,

I'm not sure it would require a full 'article' but ....

Could you provide a post that details your choice in equipment for 'top starting' the gas powered machines?

- Starter
- Battery (e.g. Finer Edge kit, etc)
- Start shaft interface, etc.

Thanks!

[Doozer]

I think a good fleshed out discussion on oil would be a good one. With some scientific data, not company propaganda, that shows why one oil is better suited for R/C applications than the other. I've seen a few oil suggestions get poo poo'd when it's clear they've never been tried. Just want to know why?

Some oils I'd like to see discussed (I'm sure there are others):
Blue Marble
Royal Purple
Pennzoil Marine 100% Synthetic
Echo 100% Synthetic
Poulan 100% Synthetic
Amsoil
Klotz

Also, Break ins. We still have a sticky in the gasser forums that recommends Lawnboy Ashless first, then a switch to Synthetic https://www.helifreak.com/showpost.p...47&postcount=1, yet we have a few of the manufacturer's here saying that's not the way to go. That's a little confusing.

[carey shurley]

Could you provide a post that details your choice in equipment for 'top starting' the gas powered machines?

here ya go: equipment for starting gasser

[brw0513]

Would it possible to do a topic "should I choose a 600 or 700 size gasser model"?

Your thoughts on build cost, crash cost, driveline options and expected flight envelope performance would be appreciated.

[carey shurley]

okay sure. I'll work on it!

[sps3172]

How soon do we get to see your pics of the Whip Gas construction process?

[carey shurley]

well, not until I build one......

sorry don't mean to be flippant. As of right now there is only one model and it belongs to one of the designers Chris Lund. After they finalize exactly what production is going to look like it will make sense to have some build documentation. Actually I'm planning some interesting stuff!

[brw0513]

Carey,

I'd also like to know about power and torque curves vs gearing and headspeed selected for these gasser models.

No need for absolute values but it would be good to see the type of theoretical power and torque curves that standard motors and tuned motors produce.

In my mind, I think the engine tuners are trying to build an engine where the peak power arrives around 1000rpm or so above the point where maximum torque is made and the gearing puts the desired headspeed right at the point of max power.

Am I right or am I dreaming?

[carey shurley]

within the next few months you're gonna start to see actual power/torque graphs here for both stock and modified motors.

you're right the key here is to match the output of the motor to a gear ratio that puts the rotor head speed where it needs to be for flight performance and keeps the motor in its power range.

I'm hoping we start to see vendor recommended combinations of a specific engine, a specific gear ratio, a specific rotor blade length and a specific exhaust system for a given flight style.

[brw0513]

Originally Posted by carey shurley

I'm hoping we start to see vendor recommended combinations of a specific engine, a specific gear ratio, a specific rotor blade length and a specific exhaust system for a given flight style.

Now that would really advance the hobby. Kinda like going from "plug and pray" to "plug and play".

And what about the benefits of semi-symmetrical blades for sports flyers?

[brw0513]

One other thing I'd like to see discussed is the run-in procedure for these gasser engines. These engines are not necessarily simple things in our application especially in the hands of the inexperienced..

Surely there must be some science to running in an engine and not just a black art?

And why can't we have a some sort of exhaust gas sniffer that shows an amber LED for rich, green for "just right" and red for lean? Perhaps the sniffer needs to be calibrated for the combination of fuel and type of oil and duty etc, but it can't be that hard can it?

[carey shurley]

Semi-symmetric blades - I love them, as a sport flyer they are fast and don't use as much power but they aren't appropriate for a lot of the current maneuvers that pilots want to do

run in - I suppose I could do something on this although the "tuners" all include detailed break-in/run-in instructions with their motors

[brw0513]

Carey,

One thing I'd really like you to discuss is how a "tuner" is producing their power and torque curves i.e. the physical hardware used to do it.

I have a gasser project underway. There are a few issues to address for sure, but one big unknown for me is the actual power and torque output of the chosen engine (Saito FG-14B). If those were known based on some real diagnostic testing, then deciding on gearing and blade length would be much easier to identify.

So how about it - can you give us some detail from a willing "tuner".

Ultimately I'd like to either build my own dyno (if practical) or perhaps even better, send my Saito engine to a tuner and pay a reasonable fee for power and torque curves to be produced. Do you know anyone?

Thanks.

[carey shurley]

good luck and have fun with your project helicopter

I'm not aware of anybody who would commercially have any mods for that motor.

Having read countless threads about folks trying to use these converted airplane motors and having flown a 4 stroke XCell for a while, I think you're in for quite a challenge. But then thats part of what the hobby is about eh?

over the next few months, I'll have access to some real information about power/torque which I'll share as appropriate.

[Azalin]

Carey the break-in is still a huge mystery for most users. Me for example. I did break-in once and now again but i still have questions how to break-in a motor correctly. Maybe you should start a topic about this. Especially for the new carbs like WT990-WT813.

Suat

[carey shurley]

Hey Suat

okay, I'll put that on the list

[cdl]

Originally Posted by brw0513

Carey,

One thing I'd really like you to discuss is how a "tuner" is producing their power and torque curves i.e. the physical hardware used to do it.

I have a gasser project underway. There are a few issues to address for sure, but one big unknown for me is the actual power and torque output of the chosen engine (Saito FG-14B). If those were known based on some real diagnostic testing, then deciding on gearing and blade length would be much easier to identify.

The only physical hardware I know of is some sort of dyno, or a helicopter itself. The mechanics of dyno's are fairly simple and inexpencive. The large expence comes with the required data aquisition system. We used a system called LabView in college that would do it, but it's not at all cheap by the time you get all the hardware.

What I would do is design your mechanics to except a large span of gear ratio and experiment with the helicopter itself to come up with something that works. Put the tall end of the ratio range at airplank type rpm and give yourself room to go shorter. Stock clutch parts might be a problem and lower rpm's so be aware of that as well.

It'll take some time, trial, and error but a Satio FG powered helicopter would be really cool! Let us know how it goes if you take on the project.

-Chris Lund

[brw0513]

Thanks Chris for the reply. Are you the Whiplash designer? If so then you've got a pretty good job.

I have access to some sophisticated data acquisition equipment at work. I test the safety against derailment performance of trains, but I spend lots of time day dreaming about model heli design!.

In my mind, once the properties of the suitable dyno are known, all that is really needed is to measure volts, amps and speed so an Eagle Tree logger would do. But there is a big gap in my knowledge about making a suitable dyno. And surprisingly there is not too much credible info on the www about making the sort of dyno I think I need.

The other thought I've had is to buy a set of postage scales and actually measure lift in "kg". If the heli mechanics were fixed to say a 15kg mass and then this was placed on the scale, I could then simply read the mass that "comes off". I could then plot lift vs head speed and motor speed for different gear ratios and blade lengths. The shape (peak and slope) of those graphs should tell a story. Of course making use of all that data is the real trick. But I really enjoy playing such games.

Thanks for the tip about gear ratio and engine speed.

I plan to use a Trex700 clutch bell and start shaft arrangement with a Lynx clutch. Candidate helical gears are available but would need to be bored to suit. Clutch clearance is another question as is cooling requirements.

Based on my research to date, it seems the Synergy N5 airframe is a good candidate. To start testing I'll be looking for blades around 550mm long, spinning around 2400rpm with an engine speed around 8400rpm.

I am very keen on the project. I have purchased an N5 airframe and I'm running in the Saito engine now. It really is a beautiful engine.

If anyone can advise what the clearance between the clutch and liner should be then I'd be happy to hear it. I suppose I could mount the clutch on a dummy shaft and spin the lot up in the lathe to around 4000rpm and measure how far the shoe moved out.

Ideas, ideas. Just wish I didn't have to work 8hrs a day at work. Sure eats into my hobby time.