YT / ESM Hurricane - Laser 200 in-line twin

[Ron Gray]

A bit of paint makes all the difference

 

 

Looks OK apart from the door panel doesn't line up due to the scale of the canopy!

 

 

Back onto the cowl, filled and sanded

 

 

Holes cut for front pot and needle

 

Edited September 4, 2022 by Ron Gray

[Peter Jenkins]

Good work Ron.

[Ron Gray]

Not a lot of progress due to being away for a few days plus 'other' events.

 

Exhaust extensions machined and fitted and plumbing all done.

 

 

 

 

[Paul De Tourtoulon]

Don't worry about progress, just seeing that lovely work of art in the morning is a nice way to start  the day.

[Piers Bowlan]

Beautiful work Ron, it will look and sound amazing. If I may ask a silly question, do you think the rear cylinder may get a little warm in there, or am I missing something (probably)?

[Ron Gray]

@Piers Bowlan without correct ducting in the cowl it will cook! The idea is that the incoming air is forced to the ‘cool’ side of the engine by blanking off part of the intake. The air is then channelled through the cylinders by ducting. The hot air then escapes through the firewall holes, into the fuse where it can exit through an opening above the tailwheel (although I maybe changing that to allow it to escape through the wing into the belly rad).

 

Some pics from my other Laser in-line installations may help explain it better.

 

Mustang

 

 

 

Sporster

 

[Piers Bowlan]

Ah ha! Thanks for that Ron, a very comprehensive answer 👍

Edited September 19, 2022 by Piers Bowlan

[Paul De Tourtoulon]

Will you be installing a small 12v ventilator in the fuselage ?.

[Ron Gray]

@Paul De Tourtoulonthat was something I had thought about installing in the Mustang, in fact it was going to be a small edf if I found overheating problems. Fortunately no such problem with either the Sporster or the Mustang as long as they don’t sit on the ground, with the engine running, for too long! I may well have to revisit this for the Hurri!
 

However this is the dilemma I’m now faced with the Hurri, unlike the other 2 it doesn’t have a chin air intake and elsewhere in this thread various suggestions have been given about how I could get over the problem of a lack of air intake. The fact that the front cylinder head protrudes from the cowl reinforces my thinking that converting the model to a Tropical one may be the answer as the under cowl air intake / rad will hopefully give me a chance to form a mini duct to separate incoming air to direct some to the rear pot. Obviously internal baffling will still be required.

 

The initial flights will be made (this week?) without the cowl in place to make sure the motor is running OK

[Peter Jenkins]

How about a NACA intake?

[Ron Gray]

Placing one behind the front pot would work but would lose some efficiency as it would be on the ‘slope’ of the cowl underside. 

[Ron Gray]

First run of the engine in the garden!

 

 

Second run

 

 

[Paul De Tourtoulon]

Nice Ron, but you do frighten me switching the glows on a flooded engine with your face in the line of the prop, I always hold the prop I have had 2 and 4 strokes

fire up on me when turned on and I once had a 3.5cc car 2 stroke start when I put the glow driver on it.

[Ron Gray]

Never happened to me Paul but never too late to learn from other’s ‘happenings’!

[Peter Jenkins]

Well done Ron.  Great to see the engine burst into life on the first application of the starter motor!

[Ron Gray]

Thanks Peter but it is a Laser after all! To be fair, Jon tunes the engines before they leave the factory so all a bit ‘plug n play’ really!

[Nick Somerville]

Love the way you give the engine a few strokes before firing it up, Ron. Sounds very nice.
 

Lots of wire dangling about your starter. Popped my battery in a simple box and mounted it below the starter. Has a nice weighty feel when offering it up to the spinner.

[Nigel R]

16 hours ago, Paul De Tourtoulon said:

I once had a 3.5cc car 2 stroke start when I put the glow driver on it.

 

Can do one better.

 

I had an OS 61SF fire and start without the glow connector anywhere near it.

 

It had run a bit rich when starting up first time. I pulled the glow stick off and a few seconds later it stopped, on compression. I presume it was simply the heat in combustion chamber that set off the partly compressed fuel/air mix in the chamber.

 

Cue rock steady idle... "Nothing to see here, guv."

Edited September 22, 2022 by Nigel R

[Ron Gray]

Mine did have the JE metal frame on it but a friend reversed over it a while back nd I haven't got round to fixing it! Dangling wires will be sorted!

 

Cor is that a scale prop in the background Nick?

[Ron Gray]

Hmmm, just weighed the Hurri, 8Kg 😲 The later ESM ones (post 2016) were a lot lighter.

[Peter Jenkins]

Hmm.  going to compromise vertical performance then!

[Chris Walby]

At 17 1/2 lbs (8kg) IMO it will fly very scale as I have not seen a full size climb vertically for long. If the inline is anything like the FT and big singles then there is plenty of grunt (torque) it will pull the hurrie along a treat.

 

I did wince with the starting technique as it only needs to fire once in either direction and the result would be painful at least. Did notice connecting the glow connectors were not powered so appreciate getting close not being an issue. IMO I don't like the use of tools as retaining devices especially on each wing as if one comes out the model will start to rotate around the other.

 

Did it need any lead to achieve C of G out of interest, just I was surprised with my FT200/Eurobat that I needed nearly a pound of lead, but then again the inline is quite a bit heavier? 

[Paul De Tourtoulon]

Watch carefully  the video Chris as he leans over to turn them on,,,

[Peter Jenkins]

Chris, the issue of power is so that you can fly a decent loop without the model's airspeed decaying too much.  I flew a 60 size Spitfire that had an OS91 FS and that would not even do what a full size Spit could - loop from horizontal flight!  I had to divebthe aircraft to pick up speed first. 

 

I know that full size could not do vertical climbs forever but apparently a well flown Spit could pull to the vertical and do 3 rolls and recover without stalling.  That's in Bader's book Reach for the Sky.  Bader hadn't msnaged it but the expert aerobatic pilot in the Squadron did.  I don't know if the Spit was fully armed and no ammo could make a big difference to vertical performance.  I suspect it might have been armed as during wartime even just doung a bit of continuity flying they probably didn't want to get csught in the air unarmed.

[Jon H]

6 minutes ago, Peter Jenkins said:

  I flew a 60 size Spitfire that had an OS91 FS and that would not even do what a full size Spit could - loop from horizontal flight!  I had to divebthe aircraft to pick up speed first. 

 

 

oof. I would expect an 80 to pull a 60 size spit all day long. Your 90 must have really been on the struggle bus, that or the model was mega heavy. 

 

I would not expect the 200 to be short on power even if the hurricane is 20lbs. Sure it wont have infinite vertical, but the 240v in my 23lb 88inch hurricane offers me more than enough power for scale hurricane flight. If it were a sea fury it would be another story, but its fine in the hurricane.