91" SkyWing ARS 300 Assembly Thread

[AKNick]

Hey Nick,

I’m running the same plane and motor as you, I’m even running your ignition mount. I haven’t had any noticeable heat issues in the cowl. My is engine well baffled. All the cut outs are open under the fuse with an RE3 in the tunnel.
Normal CHT has been under 200F in the air.

Thanks for keeping us posted! I'm very curious to see what you find especially since I'm running a similar setup!

Yup, I’ll keep you posted.

 

[AKNick]

Been plying with some 3DP Air Dam Ideas.
So hot off the bed are two creations. I like the curved one better I think

The though would be to glue the flange on the inside of the cowl.

 

[Snoopy1]

Love the curved one that will do the trick. I always make them out of balsa. Difficult to do and get the curvature just right and fit the cowl and very susceptible to damage .

 

[AKNick]

Love the curved one that will do the trick. I always make them out of balsa. Difficult to do and get the curvature just right and fit the cowl and very susceptible to damage .

I’ve made them out of carbon before. Thought about using the 3DP part as a mold of sorts... this one is kinda heavy

 

[Snoopy1]

Looking at it in your fingers the thickness can cut by half at least and do you really such an elaborate flange. The flange only needs to be 1/8 wide and the bring the deflector up through the bottom of the cowl and glue the flange to the inside of the cowl.

 

[AKNick]

Call me crazy, but I think my left/front cylinder is pinkish. I must have a overheating issue. It's tuned well in my opinion, and dies like the throttle cut was hit. Seems random, but as this puppy breaks in the engine gets rich, so I lean it out to compensate as the rings set. Doing so the cylinder may be running a tad hotter than before and possibly even hotter in the air without me realizing it. I do vaguely remember me thinking that it was pulling out of a prolonged funnel hover slow... probably overheating it in the process. It's baffled, but I'm really thinking it's time to open up some exhaust air and this will fix my dead stick issue. Anyways, just sharing my thoughts. @Das_Stig you got me thinking that maybe I should consider telemetry CHT for fun and education.

@Snoopy1 yes, The idea was to glue the flange on the inside of the cowl. My CAD skills suck when it comes to complex curves on a free program. The overall thickness and height of the dam needs to be reduced. My initial thought was that it would ramp up and prevent the exhaust residue from entering the exhaust air hole.

I keep debating if I should open up the tunnel and add the air exits provided instead of hacking the cowl. I can add air dams to the front of those exits to compensate. But it may help suck the hot air out of the cabin as well. Crazy, but my research shows that air dams can reduce cylinder head temps 20-30 degrees - that seems like quite a big number to me.

 

[Snoopy1]

All I can tell you is it made a big difference on my planes but how much I am like you no telemetry. I have done it on all my planes. Look at my Timber cowl I made one for it as well. You will also see that the side are carried backwards that made a big difference, it stops the air from wrapping around the deflector and back into the hole.
Sorry just went to look at it, it is not in the cowl but in the fuselage.

 

[acerc]

On all of mine, of which have telemetry, the duct/ram or thingy on the bottom really does help in creating a vacuum and pull the air out. Could not imagine not useing temp sensors at a minimal to know what is going on. Without sensors everything is a guess, and in my case a lot of wrong guesses. These wrong guesses also included airspeed, altitude, power consumption, and rpm. Not anymore!!!

 

[Das_Stig]

It’s definitely not a bad idea, to have a CHT. I’ve never had it before this engine and airframe either, but I’m glad I do. Plus it’s super cheap to add the sensor if you have a 12310t or similar rx. The first few flights, I set the radio up to speak the temperature every 30 seconds to me. I kind of got a feel of what to expect, and set an alarm based off that. I also have a switch set up so that when I throw it at any point in time the radio will speak the current temperature to me.

Do you have the big round hole blocked off on the front of the Cowl? If not you should. You want all the ram air to go through those cylinder fins. I think having that hole open will create a higher pressure within the Cowl and prevent air from flowing through the fins efficiently.

 

[AKNick]

Okay, I'm convinced. Ordered two cyl temp telemetry sensors for my Futaba 18SZ. Not sure what I'd do without TowerHobbies coupons to make it happen. Also ordered a HV Tech Aero, curious if it gets rid of that little tiny hesitation I'm hearing and cannot seem to tune out from idle to WOT. All while opening up the cowl and adding a curved air dump lip of sorts. Victory will be mine.