Jump to content

Twin glow motors for warbirds?


Edgeflyer
 Share

Recommended Posts

I'm wondering about the feasibility of using twin glow motors around the 15cc size in a large warbirds twin, like the BT 81inch mosquito or the AMS Tigercat. I could go with 2 OS 91FS or 2 Saito 82s. The issue as always is noise. What chance getting below 82db? Maybe 2 Axi 4120s would do but not as nice. Any thoughts please?

Link to comment
Share on other sites

My club's secretary flys a lovely Black Horse Mosquito with twin ASP fourstrokes, 60s I think, might be a tad bigger. As far as I'm aware he's never suffered an engine out, but then he's very diligent with the setting of them and took particular care with their installation. Sounds beautiful and is not at all noisy.

Link to comment
Share on other sites

Twin four strokes are the ultimate Warbird power and the sound is marvellous. They are not common I suppose mainly due to cost. If you build one you will certainly get an audience . I must agree that the sound of two decent 4s engines in a Warbird really positively adds to the impression of the model . I’m afraid electric Warbirds are far less impressive to me.

Link to comment
Share on other sites

Posted by Tim Flyer on 10/10/2019 22:24:50:

Twin four strokes are the ultimate Warbird power and the sound is marvellous. They are not common I suppose mainly due to cost. If you build one you will certainly get an audience . I must agree that the sound of two decent 4s engines in a Warbird really positively adds to the impression of the model . I’m afraid electric Warbirds are far less impressive to me.

To be fair, electric does have its place in the warbird scene, but in what I call 'convenience models'. Smaller, possibly foamy warbirds that often have an appearance and performance and that will be fine as hack models for a bit of fun. Anything decent needs to be IC in my opinion for all the reasons that we've discussed at length elsewhere. No right or wrong with this, it's what works for the individual and what one is striving for.

Link to comment
Share on other sites

Either glow or electric work very well, electric is far more reliable. Glow requires constant maintenace to ensure reliability and also you need to take your time on the engine set up to ensure reliability and to know when not to fly when things are not right. I lost a big 120" DC 3 when 1 90 quit in a climb but it was my fault as I had been pushing the limits. My Brian Taylor Mosquito was lighter than the original and easy to fly on electric as you did not have the pronounced swing on tke off with glow motors, The rudder is not very effective at low speed. Choose the right airframe for the motors. Vibration is a lot more on a twin._dsc3386.jpg p1010347.jpg

Link to comment
Share on other sites

I have a foot in both IC and electric camps with my 81" BT Mossie.

It originally flew with RCV 60SP engines for a number of years although these were at the lower end of the acceptable power spectrum. I had an engine out incident a couple of years back and could not get quite back to the runway and the model landed in the rough pasture about 30ft from the edge of the runway. There was bad damage to the wings so I had to rebuild the wings and after the engine out I rebuilt it as electric power. Interestingly, the electric version weighs 17lb 12oz ready to fly, the IC version weighed exactly the same dry (without fuel).

The RCV SP engines being the geared ones used 16x12 props running at peak 5,500rpm, so I have kept the same large props and chosen the motor KV appropriately. Hyperion ZS 4025-16 320kV motors with 16x12 APC E props driven by 6S 4000mAh batteries through HobbyWing Platinum 80A V4 ESCs. Measurements gave 6,450rpm at 22.3V with 47.5A, so about 1050W each = 2100W = 118W/lb. I am waiting for a gap in the wind and rain to remaiden it.

RCV 60SP engines during original build1431 engines installed.jpg

Motors and ESCs during rebuild1492 motor + esc (custom).jpg

Battery hatch cut into cowl and box1495 left nacelle battery (custom).jpg

Ready to fly again1501 ready to fly again (custom).jpg

Link to comment
Share on other sites

It will come as no surprise that i will always vote i/c for twins. Over the years i have owned 6 multi engine models and am yet to loose one to an engine failure related crash. My first model did suffer a few engine out related spins but once i started ignoring the commonly held views of how to handle a single engine twin and resorted to my current method of flying flat out on the remaining engine to keep the speed up my problems were solved.

While its true that multi engine ic models are a different proposition to a single none of it is difficult and once you get used to it a twin is no more daunting than any other model.

With all that said, i twin trainer of some sort is always a good idea before you go all in on something like a mosquito

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...