Where to start

[Deskpilot]

As Nomis or Simon, you're very welcome.

 

 

[Marty_d]

Hi Nomis (No missus???;-)Thanks for the heads up, I'll try to locate him. There's very little on the web re the Wyvern and short of revisiting the UK to see the real thing..........

Safe flying Doug

Hi Doug,

I was looking up George Markey when I found this thread, Pylon500 said he'd built plugs for a glass Spitfire.

 

Noticed your droolings over the Wyvern with its contra-rotating props, admittedly from 9 years ago.

 

If you're still interested in this aircraft then new technology may help - have a look at www.contraelectric.com . I'm actually fascinated about this and waiting to see what their retail price turns out to be when they take this to market.

 

Cheers, Marty

 

 

[Deskpilot]

Way to go Marty. We need lighter batteries before I'd spend money on going electric though.

 

 

[facthunter]

Contra props were used when single engine fighters became difficult to manage with High HP motors in wave off situations. Also used in the Fairey Gannet twin mamba engine arrangement. I wouldn't see them as practical in the weight and complexity, reliability stakes or needed in a practical sense, or from a looks' perspective. If you want the radial look and sound the Rotec is there. That's why it was produced, but a bit weighty. Need plenty of wing area. Lysander replica? Nice tandem Difficult build.

 

You could built your own small inline 4 based on a Henderson or Indian 4 or use a Vee twin lawnmower engine. The 582 Rotax is best for power/weight An outboard Rotary with parts from an auto trans for the reduction is also powerful, reliable and NOISY.

 

The V twin Guzzi's (Lario) the small one might be a small unit cheaply set up. Nev

 

 

[Litespeed]

If you are after a 4 cylinder in line then the BMW k 100-1200 rs motors would be the go. The big ass flywheel and car type clutch weighs a lot so bin that for reasonable weight. The have very big torque down low and are not a high revving motor for their power 100-130hp. The 1200 is best. All are bosch injected and very, very bloody hard to kill. They are nick named the brick, they are horizontal ie cylinders lay on side. Very compact.

 

A 100,oookm on one is considered run in, many have 300,000 plus and still strong as a "brick Shitehouse".

 

Yes they are watercooled. The 1200 motor can be had for $1000-2000 with everything needed bar a redrive.

 

The lario is a sweet little motor but it would be quite expensive to get one, quite underpowered even the brand new version at 750cc is considered gutless. Older models command stupid money due to cafe racer crowd and L plate legal.

 

 

[Marty_d]

Way to go Marty. We need lighter batteries before I'd spend money on going electric though.

True, there's a way to go on battery technology, but even with current (pardon the pun) ones the Pipistrel Alpha Electro has about 1.5 hours worth. I'd be happy with a warbird copy that gave me 20 minutes in the air with 15 backup. Obviously powering the big speakers with the Merlin soundtrack would take some juice...

 

 

[Litespeed]

The electric airplane is not science fiction but the range is not great yet- but given the big weight diff for the engine it does mean quite a few batteries. And they can be placed for perfect weight balance.

 

Next 5-10 years will see great strides in battery weight and capacity and solar cells on the wings.

 

 

[Deskpilot]

Failing that, a D-Motor should be the way to go. Side valve engines don't rev high but have low rev grunt. My Dad once had an Austin with a 750 cc motor. That thing would start at the bottom of a 8 :1 hill with 5 on board and go straight up albeit slowly. I've seen new cars (1950's) stall part way up the hill.

 

 

[facthunter]

That's not quite true DP. JAP made competition sidevalves that revved high. Cotton 350 late 20's Zenith , Brough Coventry Eagle etc as 1,000 and 1,200 CC Vee Twins in the 20's and the WR and later 750 Harleys and 830 cc KRTT 63 HP and capable of 10,000 rpm in ultimate form. The Hudson Terraplane was a 110 HP motor of 2.4 litres standard out of the box with a single Carburetter. Extensively used in hillclimb specials pre and post WW2. They don't breathe well but they can have wild valve timing due to the direct acting valves. Can't run high compression because of the large combustion chamber area and are inefficient for the same reason. Nev

 

 

[Deskpilot]

I bow to your superior knowledge Nev. I'm more familiar with conventional flat heads. Had a 3.3ltr straight 6 in a Nash Rambler many years ago. Would pull the side of a house off. It's a pity the 'T' head didn't get developed as that was another awesome, simple flat head with the X flow breatherbility., and higher revving I believe.

 

 

[facthunter]

Mostly back in the teens . White and Poppe... Look it up. Even harder to get compression than a side valve. I don't particularly like sidevalves. They distort a lot due to uneven heating. They were part of the scene so you had to work on them in those days. They were cheap to produce and compact . The first Lycomings were sidevalve and some were built by Indian under licence. 2 bearing cranks which were adequate for the time and power delivered.. Some of what you read these days is based on hearsay. A reasonable OHV will outslog a sidevalve if it's designed to run slow, because torque is based on volumetric efficiency, and the OHV breathes better every way. The reliability thing is related to valve stem breakages. A common thing in the early days when refractive metals metallurgy was not well developed. They ran a cast iron head to which a steel stem was riveted, as an exhaust valve . This arrangement often failed and the bit falls into the cylinder with an OHV. Not so with a sidevalve so the "more reliable" concept originated. The "F" head (pocket valve ) is in between. The first "Wright" engine built by a bloke called Taylor was an F head. nev

 

 

[Marty_d]

a bloke called Taylor was an F head. nev

Er... so it wasn't a very good engine then??

 

(Sorry Nev. Couldn't resist.)

 

 

[facthunter]

It was a pretty poor engine really (ran very hot as it had an antechamber for combustion) and quickly superseded by something more conventional and more powerful.(Still built inhouse) Others offered to build an engine, including Glen Curtis who probably would have done better, but ended up being a fierce competitor. Nev