Cheap Multi time in the Cri Cri?

[FRQ Charlie Bravo]

Whilst "studying" I came across CAO 40.1.0 Appendix VI (page 43) and noticed that the CRI CRI aka the Criquet (http://en.wikipedia.org/wiki/CriCri) could be flown under a SE<5700 kg endorsement. Upon further investigation I learnt that a Frog strapped 2 AMT Olympus Turbines onto his (leaving him with 35 kg thrust). Multi-Turbine time sans a Multi endo?

According to another thread (http://www.pprune.org/2052939-post5.html) the reason one doesn't need a special endorsement is that with the failure of one engine there is bugger all asymmetry due to the prop wash (non turbine) simply blasting the empenage on the live side and correcting the yawing tendency.

I'm certainly not seriously advocating getting one of these to get 500 hours ME PIC but I do wonder if there's a market for people who are a bit shy on numbers to apply for a job who would otherwise be suited. I'm thinking of an instructor mate of mine (with about 1500 TT) whose employer recently had to hire a Duchess to get 50 ME PIC (to get his META I think) so he could instruct on a Baron.

FRQ CB

http://www.amtjets.com/cri_cri_10_gallery.jpg

[FRQ Charlie Bravo]

If you bought one of these overseas would you ferry it or just pack it into you checked luggage?

JK, the range is about 500km max

FRQ CB

[Howard Hughes]

Range is not a consideration if you are only worried about 'building time'!;)

[Jabawocky]

I want one!

Cool toy!

J:ok:

[Ultralights]

there is one at YHOX, and yes, you can log command twin time in one if its VH registered, i have heard a few stories of pilots in the US buying/building one and using it to gain twin time.. though it would be interesting if asked what type it was in an interview.

[Howard Hughes]

No room for internet and other cool gadgets though Jaba!:ok:

[ZEEBEE]

T'would be a bit noisy I would have thought!

You should be able to log multi-time just for the noise alone

[Unhinged]

with the failure of one engine there is bugger all asymmetry due to the prop wash (non turbine) simply blasting the empenage on the live side and correcting the yawing tendency.

That doesn't make sense. If there is an engine failure, the aircraft will start to yaw initially due to the turning moment of the remaining thrust pivoting the aircraft about its centre of gravity.

You might want to argue that it's only going to yaw a small amount due to the minimal thrust, but that doesn't change what happens next.

Next, as the fuselage has yawed and the engine is still bolted securely to it, the thrust line of the working engine/propeller has not stayed where it was; it has also yawed - the same amount as the fuselage.

Since the prop wash has turned with the fuselage, it has remained generally parallel with the fuselage, and there is little or no sideways force vector from the prop wash pushing against the yawing moment from the asymmetric thrust.

[Jabawocky]

No room for internet and other cool gadgets though Jaba!http://static.pprune.org/images/smilies/thumbs.gif


Good point HH,

Won't be able to leave the circuit! :eek:

J:E

[Torres]

Bobby Gibbes built a Cri Cri in his living room at home in Sydney over 20 years ago:

http://img.photobucket.com/albums/v315/Woomera/PPRuNe/BobbieandJeanie_0003.jpg

He used to get real p!ssed when I referred to it as a twin engine lawn mower! :}

It is on the VH Register and last heard of was still flying somewhere in Australia.

[Capt Wally]

christ that's incredible, now there's one happy man, beer in hand, plane in his lounge room & a woman who's not holding a shot gun at him saying...'get that bloody thing out of my living room' !!

I've just test flown a 1/3 scale PA18 that looks as big as that Cri Cri! Keep an eye out for the article in the current Airborne Mag for modelers!:ok:


CW

[Torres]

Jeannie was not impressed when the living room wall had to come down to get it out!

Found a Cri Cri on the CASA Register (http://www.casa.gov.au/casadata/regsearch/airsresults.asp?VHin=&framein=all&manuin=&modelin=Cri+Cri&regholdin=&regopin=&serialin=&num_results=10&Search=Search) but I don't think it is the one Bobby built.

[pw1340]

don't try this at home

YouTube - World's Smallest Twin (http://www.youtube.com/watch?v=WcPlXNjmmco)

[mustafagander]

Torres, the Cri-Cri with the VH rego belongs to a QF pilot.

[Ultralights]

Since the prop wash has turned with the fuselage, it has remained generally parallel with the fuselage, and there is little or no sideways force vector from the prop wash pushing against the yawing moment from the asymmetric thrust.

the prop wash off both engines deflects off the side of the canopy, as the engines are very close to the centreline of the aircraft, and its the deflection of the prop wash off the canopy that counteracts the asymmetric forces of a failed engine

[Capt Wally]

simply put, that guy is nuts !:bored:
Amazing video, tnxs 'pw'


CW

[Unhinged]

its the deflection of the prop wash off the canopy that counteracts the asymmetric forces of a failed engine

Maybe. For that to be true, the canopy would have to be sufficiently far behind the centre of gravity that the moment generated by the prop wash pushing against the canopy equalled the moment generated by the asymmetric thrust of the working engine.

However, in the photos the canopy appears to be to be only marginally behind the likely position of the CofG; so its distance to the CofG is less than the distance from the propellers to the CofG. And the sideways force generated by the prop-wash is certainly less than the total thrust from the propeller/engine combination.

It seems very unlikely that (the small amount of sideways force x the shorter distance from the canopy to the CofG) > (the larger forward component of propeller thrust x the longer distance from the propeller to the CofG)

I don't know why the CRI CRI gets the exemption in 40.1.0, but obviously it works in practice. The explanation so far is nice, but it seems unlikely to be the correct one.

[BBMouse]

Have a friend with a cricri who says that it definatly yaws in the opposite direction to a conventional twin for the reasons stated above.

[the wizard of auz]

Capt Wally I have a 33% J3 Cub that is about the same size as the Cri Cri. DZY 48 Twin Gasser about 1/3 throttle will pull up 6M ASW28, Ash26 and Discus II. I reckon I could tow up that Cri Cri with half throttle. :}
Waiting for my RCMA and Airborne mags with interest now (PA 18 was my next project). :ok:

[Capt Wally]

I once thought I might build an R/C model of the Cri Cri, but then again building a scale version a 1/3 BIGGER than the full sized one would still be tiny!:)
Love the jet powered version, a few hrs on that & a CMD on an A380 ought to be easier!:)

CW

[Howard Hughes]

I'm sure the A-380 is EASIER to fly than the Cri-Cri, although perhaps not as manouverable...;)