Jet powered Pitts Special

[Peter Wedlake]

Just because you can...

 

https://www.bbc.co.uk/news/av/uk-england-hereford-worcester-64788578

[John Wagg]

So do the jets just drive the prop' or do they assist as well?

If the jets are propulsion on their own then dump the prop'. ?

 

[Outrunner]

Looks like they are in addition to the prop

[John Lee]

Yes, the jets are supplementary to the main 8.5litre(!) Lycoming piston engine. Much more detail of the project at Rich Goodwin's website

[John Wagg]

9 minutes ago, John Lee said:

Yes, the jets are supplementary to the main 8.5litre(!) Lycoming piston engine. Much more detail of the project at Rich Goodwin's website

Thanks for the link. 👍

[Peter Christy]

1 hour ago, John Lee said:

Yes, the jets are supplementary to the main 8.5litre(!) Lycoming piston engine. Much more detail of the project at Rich Goodwin's website

Capacity doesn't mean that much in aero engines when compared to cars! Going back several decades (!) when I was learning full-size, the trainer I flew had a Lycoming of around 5.5 litres (I forget the exact size, might have been 5.8), but it only developed just over 100 HP! They were designed for rugged reliability above all else, were noisy and rough, but like a tractor engine, just kept on going!

 

Mind you, bearing in mind how reliable modern car engines are, I'm amazed that more have not been converted for aircraft use. More power, less weight, fuel injection (so no carb icing!) and so on. I know some have been adapted, but I can only assume that the powers that be are stuck in some kind of time warp....!

 

--

Pete

[J D 8]

       There is a Sterman bipe I have seen pics that has a jet mounted between the UC legs.

[John Lee]

JD8 you may be thinking of the Waco biplane that had a 3000lb thrust GE J-85 mounted underneath and a wing walker on the top! I was fortunate to see it in the USA at the Fun 'n Sun airshow and its performance was ever bit as astonishing as the specification implies. Sadly the pilot and man behind the project, Jimmy Franklin, was killed in a mid air collision in 2005.

 

 

Edited March 9, 2023 by John Lee

[Flying Squirrel]

18 minutes ago, John Lee said:

JD8 you may be thinking of the Waco biplane that had a 3000lb thrust GE J-85 mounted underneath and a wing walker on the top! I was fortunate to see it in the USA at the Fun 'n Sun airshow and it's performance was ever bit as astonishing as the specification implies. Sadly the pilot and man behind the project, Jimmy Franklin, was killed in a mid air collision in 2005.

 

 

Just had a read up on this, very interesting but with a terrible end. Quite a few scale models of the plane though.

[john davidson 1]

 

1 hour ago, Peter Christy said:

Capacity doesn't mean that much in aero engines when compared to cars! Going back several decades (!) when I was learning full-size, the trainer I flew had a Lycoming of around 5.5 litres (I forget the exact size, might have been 5.8), but it only developed just over 100 HP! They were designed for rugged reliability above all else, were noisy and rough, but like a tractor engine, just kept on going!

 

Mind you, bearing in mind how reliable modern car engines are, I'm amazed that more have not been converted for aircraft use. More power, less weight, fuel injection (so no carb icing!) and so on. I know some have been adapted, but I can only assume that the powers that be are stuck in some kind of time warp....!

 

--

Pete

\The Diamond Twin powered by two diesel  engines bucks the trend, used by the local flying school for twin training and seen over my house several  times a day, someone at the club said the other day it was so economical it could easily cross the Pond in one go.  Teknic uber whatsit

[Andy Stephenson]

2 hours ago, Peter Christy said:

...Mind you, bearing in mind how reliable modern car engines are, I'm amazed that more have not been converted for aircraft use. ...

 

 

There's a 7/8 scale man carrying Spitfire build-it-yourself kit that uses an Isuzu car engine.

[Paul De Tourtoulon]

45 minutes ago, Andy Stephenson said:

There's a 7/8 scale man carrying Spitfire build-it-yourself kit that uses an Isuzu car engine.

One was built locally at an airfield near Montpellier and actually flew.

[PatMc]

1 hour ago, Andy Stephenson said:

There's a 7/8 scale man carrying Spitfire build-it-yourself kit that uses an Isuzu car engine.

That's the Supermarine Aircraft Spitfire Mk 26b - it's 90% scale fuselage 75% scale wings - details here.

I took a photo of one (probably a Mk25) that had just landed at Archer airfield near Brisbane in 2000 as it taxied past. Unfortunately I hadn't spotted it before it landed.

[Peter Christy]

I know that at one time, some of the reduced scale American warbirds kits used V12s taken from Jaguars! Apparently the Jag V12 engine was not that popular in the USA, and quite a few car owners replaced the V12 with Detroit sourced V8s in their Jags. This led to a source of V12s available to replica warbird builders. Also, quite a few European homebuilds use modified VW engines.

 

However, that was not what I was talking about. I was considering the "big names" in light aircraft, like Cessna and Piper who seem to resolutely stick to Lycoming and Continental engines that were designed when Pontius was a pilot. They may be reliable (generally!), but so are modern car engines - which are also generally lighter, more powerful and smoother.

 

It just amazes me that general aviation still seems stuck in the dark ages! Perhaps they are waiting for electric power to mature.....

 

--

Pete

 

[Brian Cooper]

Well done Rich Goodwin. 

What a fabulous upgrade for the Pitts. 👍

[John Lee]

3 hours ago, Peter Christy said:

 

 

It just amazes me that general aviation still seems stuck in the dark ages! Perhaps they are waiting for electric power to mature.....

 

--

Pete

 

 

The main problem with adapting car engines is, in general, that they are not designed to give large amounts of power over very long periods. A car cruising on the motorway will perhaps be operating at a quarter or half throttle whereas a light aircraft cruising will be more likely to be at 75%+ power.

 

The big change in GA over the last couple of decades is the adoption of the Rotax 912/4/5 series engines. These quiet, lightweight, geared engines with a liquid cooled head use about half the fuel of the equivalent Lycomings & Continentals (and can use car petrol 'mogas' as opposed to 'avgas') . Rotax had sold 50,000 912's as of 2014 and the series are now pretty much universally adopted for all new microlight and 100-150HP light aircraft.

 

ps the electric powered Pipistrel Velis is certified & available in the UK.

[buster prop]

Even if a modern car engine was powerful enough, wouldn’t it have to have two spark plugs per cylinder? I thought dual ignition systems were mandatory for aero engines. If one system fails the engine will keep running at slightly reduced power. I flew in a Chipmunk a few years back and it had two magneto switches. How do adapted car engines work in kit aeroplanes, do they have to have different cylinder heads?

[Peter Jenkins]

It depends on the type of certification.  The much used VW air cooled flat four had a single plug per cylinder certainly in the Falke Motor Glider I used to fly.

 

Back onto the power uplift for the Pitts, we used to have one of the UK Team aerobatic pilots flying from the airstrip we use to fly from.  I calculated that he had about 350 bhp/ton whereas my F3A aerobatic aircraft had 840 bhp/ton.  That was why I could accelerate when going vertical whereas all he could do was slow down even with that amount of power available to him.    It was quite an eye opener when I first did the power to weight calculation on my model.

[PatMc]

Peter, is that UK ton, US ton or tonne ? 

Edited March 10, 2023 by PatMc

[David Holland 2]

The problem is one of a small market and a very onerous certification regime. I think Rotax originally made 2stroke engines for snowmobiles and the like. These were suitable for the first powered hang gliders and then microlights. The flat four Rotax, originally about 80hp, became the motor of choice for many homebuilds and the developing ultralight market. It has grown to 150hp with a turbocharger. I fly a Robin DR500, a beautiful dinosaur - 200hp, fuel injected, constant-speed propellor - 120 knots but using 40 plus litres per hour at £2.54 per litre, it will go faster but the fuel consumption goes through the roof. A Europa (for example) will cruise at the same speed on about 18 litres/hour. I can’t find a figure for the number of Lycoming/Continental powered aircraft sold last year worldwide but I would guess low 3 figures and shrinking. The development and certification costs would make it unlikely that we shall see any new, fuel efficient power unit any time soon.

[Peter Jenkins]

29 minutes ago, PatMc said:

Peter, is that UK ton, US ton or tonne ? 

UK ton.  The metric and UK ton are extremely close.  Isn't the US ton the same as an imperial measure? 

 

I know a US gallon is 3.5 ltr while a UK gallon is 4.54 ltr.  Odd really, you'd have thought the US gallon would have either been the same or moved up to 5 ltr to make sums easier!

[jrman]

US ton, commonly called a "short ton" is 2000 lb.

[Peter Jenkins]

Thanks jrman.  

[perttime]

On 09/03/2023 at 14:59, John Lee said:

Yes, the jets are supplementary to the main 8.5litre(!) Lycoming piston engine. Much more detail of the project at Rich Goodwin's website

 

You can buy those ATM Lynx engines if you want to.... https://www.amtjets.com/form_pricelist.php

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