RAA and Twin Engines.

[Marty_d]

The difference is that now electric is a game changer. Electric motors are extremely light in comparison to IC donks, so there's probably not a lot of difference weight-wise between one big one and a couple or more smaller ones.

 

As battery technology improves, I guarantee that people will want to start building their own multi-engine aircraft - even under 600kg - so I don't think the subject is totally irrelevant.

 

 

[SSCBD]

I think you are confusing the Beechcraft BE76 Duchess and the Piper PA-34 Seneca.Duchess

 

[ATTACH=full]49324[/ATTACH]

 

Seneca

 

[ATTACH=full]49325[/ATTACH]

No I am not - but you can ad the Seneca to the easy list.

 

 

[ben87r]

Tecnam P2006T with twin rotax 912 - MTOW 1230KG

Ok yep, certified but far from conventional.

 

 

[poteroo]

May I suggest those who have not for your birthday go a fly one, say a baron 58, an Aerostar is really fun as well, its a bit sporty, and ask the instructor to give you a engine out at height. Then try climbing and turning. Next ask him to let you fly the circuit engine out and put on a stable final flying down the centre line.

Back in the early 70's, a Baron endorsement at Jandakot , required you to identify, feather and secure one at blueline, then fly the circuit and land on the live engine. The engine was 'failed' using a mixture cut to ico with the mixture levers hidden by a newspaper held by the instructing pilot. So, you had no idea which one died and had to correctly id it. Very exciting! Luckily, in those days JT was way out in the bush so the only danger was to yourself or a few kangaroos. The Baron below was one of the many I flew at the time. It wasn't considered particularly dangerous in a Baron, but I'd be hesitant to try it on anything of much less performance. Those were the days!

 

 

 

[alf jessup]

Tecnam P2006T with twin rotax 912 - MTOW 1230KG

Yep about 400k+ each new

Between 250 & 350k usd 2nd hand

 

I think I'll by 4 of them

 

 

[Downunder]

One for you. One for me. Who are the other two for?

 

 

[Blackhawk]

I have always wanted to see twin engines with inline push/pull configuration approved for RAAus aircraft, purely for safety.

 

If you were building say, an aircraft requiring a single engine and if the design allowed; you could use 2 x engines of suitable power as an alternative arrangement

 

so long as the MTOW for its category was not exceeded.

 

Aircraft like this;

 

 

 

[Mike Borgelt]

You can treat twins in two ways: consider it a single and shut down the remaining engine if one fails or design the thing properly so that an engine failure is manageable. Two engines in a properly designed aircraft with performance margins turns a life threatening emergency (engine failure) into an in flight procedure. No brainer. Airliners all have at least two engines. RAAus should be abolished anyway along with any silly restrictions.

 

 

[Bruce Tuncks]

Yep, 2 engines are banned for "safety reasons" and the comparisons with king-airs is used to reinforce the nonsense.

 

But remember the first law of running a bureaucracy is to never make the problem go away. The problem, in our case crashes, is what gives CASA and ATSB their budgets and powers.

 

 

[Bats]

Making an engine failure into "an inflight procedure" may just be over-simplifying things a little. It is not for nothing that the fatal accident rate for light twins was (is?) worse than for singles for many years now. In my view, other than those aircraft where the impact of asymmetric thrust has been minimised, they are horses for experienced hands, not weekend warriors.

 

 

[Bruce Tuncks]

Bats, is that true for twin engines in line? or are you repeating the king-air stuff?

 

I am referring to the comment about the accident rate being worse for twins.

 

 

[Bats]

Bruce, I don't have the stats to hand, but my recollection is that the FAA stats excluded inline twins, which are obviously more benign. One of the heavyweights from Flying did an article on the subject (Collins?) and it seemed that conventional twins killed people by going over on their backs shortly after take-off where the asymmetric thrust was mishandled or speed too low, but also on approach when pilots got behind the aircraft as they started adding drag. I read a lot about the subject because a mate built a Zenith 601 and we were both rather taken with a twin version, until the realities of a short-coupled twin with smallish tailfeathers and fixed pitch props dawned on us.

 

 

[Bruce Tuncks]

I reckon you made the right decision Bats about that twin Zenith. But that video Blackhawk posted looks to me like a safer powerplant than a single engine. As long as it could climb just a bit on one engine.If it needs 2 to stay up then you have increased the risk not decreased it.

 

 

[craigL]

The difference is that now electric is a game changer. Electric motors are extremely light in comparison to IC donks, so there's probably not a lot of difference weight-wise between one big one and a couple or more smaller ones.As battery technology improves, I guarantee that people will want to start building their own multi-engine aircraft - even under 600kg - so I don't think the subject is totally irrelevant.

Fully agree! Electric aircraft will be a disruptive technology and it will be very interesting to see how the regulators (including RAAus) react to them.

 

Aircraft with many electric props are already emerging, some like drones but human scale. E.g.:

 

Volocopter I VC200 Prototyp

 

and

 

Joby S2 | Joby Aviation

 

The many engines make them much safer than even twin props.

 

 

[Aero28]

Been doodling on the computer and came up with this design, twin electrics would suit this idea .Inevitable that it will have to be put in the rules at some stage I reckon.

 

 

 

[Frankus1aust]

The Jab twin is the likely candidate. Realistically we are looking at a small LSA pool at the moment but why rule it out? The great thing about LSA is the opportunity for innovative ideas and products that would otherwise never make it through the system. I would suggest push for it but the weight limit, even if lifted to 1,500 KG's would pretty much exclude GA twins unless I am mistakened. Nothing to lose

 

 

[Deskpilot]

Been doodling on the computer and came up with this design, twin electrics would suit this idea .Inevitable that it will have to be put in the rules at some stage I reckon.[ATTACH=full]49423[/ATTACH]

Interesting design Aero, could be an illusion but I think your empennage is too small. Might I also suggest, with all the work being necessary to build it, would it not be more user-friendly if it were a 2 seater?

 

 

[Aero28]

Just for you Doug.... I ran the fattening tool over it :) now a two seater. Made the vertical fins bigger too. Bit of a trade off there, don't want them too big , might induce flutter but still need slow speed control.

 

Cheers Paul.

 

 

[aj_richo]

I seem to have this dim memory of a twin engine machine built in the early 90's, may have been by Nestor Slepcev, called it Yugo ?.

 

Australian Ultralights mag had a picture of it.. IN flight. (Back when innovation not recrimination was the in thing!)

 

 

[Birdseye]

Here's a sensible 'twin', but you wont get it down to 1320kg AUW

 

 

 

[Marty_d]

Here's a sensible 'twin', but you wont get it down to 1320kg AUW[ATTACH=full]49487[/ATTACH][ATTACH=full]49487[/ATTACH]

I think "butt ugly" is the words you're looking for there...

 

 

[Birdseye]

I think "butt ugly" is the words you're looking for there...

A child only a mother could love.

 

 

[scre80]

Here's a sensible 'twin', but you wont get it down to 1320kg AUW[ATTACH=full]49487[/ATTACH][ATTACH=full]49487[/ATTACH]

What is it?

 

 

[red750]

Fairey Gannet, a British carrier-borne anti-submarine aircraft of the post-Second World War era developed for the Royal Navy's Fleet Air Arm, also served with the RAN.

 

 

[Birdseye]

Fairey Gannet

Uses a RR Mamba twin turboshaft power pack and twin contra-rotating props. So it could be regarded as a single, but with two separate power and prop sources. It can fly on either or both.