Fly aerobatics for less?

[It flies]

Fly aerobatics for less - Dallair FR01?

What do the aerobatic pilots on this forum think of the Dallair FR-01? It is an ultralight that was designed from the outset with aerobatics in mind. It uses the 80 or 100 hp Rotax, or a special souped-up 135 hp aerobatic version of the same engine. The company plans to certify it in the UL/LSA category and also sell it as an experimental kit.




Much of the attraction of course depends on price, which I have not been able to determine. I still think this is an interesting new development.

Some more info on the company's website:

DALLAIR:::

[NigelOnDraft]

Looks interesting... Not actually seen anywhere on the website the 'g' limits it will be cleared to?

For everyday aeros, you'd expect +6/-3g... If a genuine "Competition" design, somewhat more.

If really looking at "competition" at low cost, it would "compete" with the DR-107 One Design Link - a +/-10g 160HP + VP Prop genuine contender at Advanced (maybe Unlimited). Cannot buy one new - you need to build it - but could be done for say £40K-£50K.

NoD

[It flies]

I think I read +/- 6g somewhere. In their leaflet are some more figures. A 2000 fpm climb, a 300 degree per second roll rate and a fuel consumption of 20-25 litres of automotive fuel per hour at maximum power. That should make it a lot cheaper to operate than any Avgas burning machine.

Agreed that the One Design is interesting too, but it runs on Avgas. Avgas is around 2,80 euro per litre in Holland at the moment.

[NigelOnDraft]

Agreed that the One Design is interesting too, but it runs on Avgas

Not really... it runs on whatever is needed by the engine / fuel system / what your authority allows

Lycoming engines and clones are often approved for Mogas - the rest as down to the pilot's choice and rules. Could even put another engine type in...

NoD

[It flies]

Not really... it runs on whatever is needed by the engine / fuel system / what your authority allows

True, there are alternatives. I'm just starting my aerobatic training and hourly prices are naturally quite steep. Maybe machines like the Dallair might one day offer a more affordable alternative. It looks quite a capable machine although it's still early days for the design.

[FleetFlyer]

That looks terrific. Is there a two seat version? If it can lower the cost of aerobatic instruction then it would be a real step forward.

[eharding]

+/-9g Ultimate load according to the website....nominal +/-6g operational.

Ultimate load is a bit on the low side for comfort for anything much more spirited than LAROSA.

Hard to tell from the photo, but the tail assembly doesn't look particularly robust, hence flicking it might be rather more exciting that you bargained for.

Personally, when they finally drop the atom bomb on us, I'm going to hide under a One Design. I reckon that spar will deflect anything short of 10 megatons.

Obviously, I'd rather hide under an SBach, but hiding space under those is a bit pricey.

[moreflaps]

Hmm, a rotax doesn't do zero or negative G does it? That would sort of limit the (my) aeros...

Cheers

[FleetFlyer]

I guess there's always going to be a tradeoff between weight/strength/cost.
I agree that 6G is a on the weak side, especially for a machine that looks like it could perform at unlimited level.

I wonder if the One Design could operate with the 135hp Rotax. Its airframe looks indestructible but is it too heavy for a 912?

[Genghis the Engineer]

I've no idea about this particular aeroplane, beyond what's on their website - but it does refer to fuel injection and an inverted oil system, which would be the main requirements to render an engine aerobatic.

That said, there are various aerobatic aeroplanes on the LAA list that would be very affordable on a permit within a syndicate or for a sole owner, if not within a flying school environment.

G

[BackPacker]

Hmm, a rotax doesn't do zero or negative G does it? That would sort of limit the (my) aeros...

I was thinking the exact same thing. It *might* be OK for a few seconds but since it's carb operated will lose engine power immediately, and will lose lubrication after a while.

I've never heard of a 135HP, injected, inverted oil/fuel Rotax, or even a 135 HP Rotax in general, and I can't find anything about that on their website. Maybe an uncertified aftermarket modification?

And even then? 135 HP for an "unlimited" machine? Competing against 300 HP machines that are not a lot heavier?

If this project ever takes off, it'll be a competitor to the R2160, GeneralAvia F22, Decathlon, Fuji and other entry-level aerobatics machines. And as others said, +6/-3G would be quite sufficient at that level.

[tractorpuller]

Maybe you should take a look at Dallairs website instead of the Rotax site. The 135 HP version is specially modified for aerobatic flight by EPAPOWER/SG Fly evolution.

It's not going to be competitive at an unlimited level, but should be quite capable at intermediate and perhaps advanced when the development gets further along.

The comparison of G-loads doesn't seem to take into account that the Dallair is much lighter and will fly the figures at a slower speed than heavier aircraft, hence G-loads should be lower aswell. +/-6 is ok, I would like to have the -6 in my Pitts...

[moreflaps]

I wouldn't like to be inside your head at -6G...

Cheers

[peterc005]

Looks interesting. Can't really compare it with a One Design (DR-107).

The 1D would use twice the fuel, but be capable of Unlimited aeros.

If you only used this LSA aero machine upto Sportsman, it would be unlikely to go past +4 or -1 G anyway.

Looks interesting. I have signed up for their mailing list and will be interested to see what the price is.

[FleetFlyer]

Surely if its lighter then it's design G limit is arrived at with its light weight in mind?

[Rod1]

This may be of interest to some;

silence twister homepage

Rod1

[BackPacker]

The comparison of G-loads doesn't seem to take into account that the Dallair is much lighter and will fly the figures at a slower speed than heavier aircraft, hence G-loads should be lower aswell.

I can't quite put my finger on it yet, but a nagging voice inside my head tells me that this is not always true.

Sure, the aircraft is lighter and therefore its structure can be lighter, to withstand the same G loads as a heavier airplane. F=m*a after all. So the G forces (F) that result from the G loading (a) are lower because of the lower mass (m).

But to say that the speeds are lower and *thus* the g-loadings are lower, I don't buy that. If the speeds are lower I would think that the g-loadings would remain the same but things like turn radii, length of uplines and such are smaller.

I can't quite see how you can fly a loop, starting out with significantly less than, say, 3G (which is about the minimum initial G required to do a loop in the R2160), and still fly a more or less round loop. (Unless the power to weight ratio is so that you can fly the whole loop, no matter its size, with one constant speed. In that case, anything over 1.0G is sufficient. But with 135 HP that hardly seems likely.)

The same would be true for a lot of other maneuvers, I guess.

Equally, but easier to compute: A 60-degree banked (balanced, non descending) turn requires 2G otherwise you descend. A 75-degree banked turn requires 4G. And that's completely independent of your weight or speed of the aircraft. It's just simple trigonometry: lift vector vs. gravity vector vs. bank angle.

As I said, can't quite put my finger on it yet. But I think the G loadings (and thus the G-limits) of a light aerobatics aircraft should be the same as a heavy aerobatics aircraft, assuming they're flying in the same category and are flying the same figures.

That a light aircraft generally requires a lighter (weaker) structure to withstand the same G loadings compared to a heavier aircraft is obviously true.

[tractorpuller]

I seems I didn't make myself clear in my previous post
I'm not saying you use less G for performing a loop in a slower moving aircraft, but it's much easier to put more stress on the aircraft when you are faster.
My point was actually about the truning radii you mention. You'll pull a lot more G in a faster moving aricraft for a small radius trying to stay inside the box than in a slower one. Much more than 5 G in my Pitts doesn't help much anyway, I'm just wasting energy...
Light aircraft, slower speed, tighter corners.

[BackPacker]

but it's much easier to put more stress on the aircraft when you are faster.

Well, that would depend on the stall speed of course. I would assume that the slower machine would also have a slower stall speed, and thus a lower Va and related speeds as well.

You'll pull a lot more G in a faster moving aricraft for a small radius trying to stay inside the box than in a slower one.

True. A slower aircraft will always have an easier time in the box.

[It flies]

Is there a two seat version?

No mention of a two seater yet. But it should be possible to modify the design. Perhaps if the single seater is succesfull in the market.

If it can lower the cost of aerobatic instruction then it would be a real step forward.

That is exactly what I was thinking.

Hard to tell from the photo, but the tail assembly doesn't look particularly robust, hence flicking it might be rather more exciting that you bargained for.

They have tested it the old fashioned way

Hmm, a rotax doesn't do zero or negative G does it?

The engine is modified by the Italian company Epapower. Modifications include enlarging the capacity to 1500cc and fitting electronic fuel injection and an inverted oil system.

SportAvio



The Silence Twister and the B&F Fk.12 Comet are the only competitors I can think of. But they are more like fun planes that can do aerobatics. I think this one is designed as a dedicated aerobatic aeroplane that should be competitive up to intermediate competition.