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Sprite Aviation Merlin

Posted: Thu Dec 03, 2015 12:23 am
by ColinC

Did anyone else take a good look at the Merlin on display at the Flyer show at Telford last weekend? I have to say that I wanted to bring it home. It seems a very well thought out and practical SSDR, appealing to me because it was very conventional in stark contrast to the E-go on the adjacent stand. That's a design achievement, but doesn't seem as practical, also so very much more expensive.

What is the feeling about engine choice? That Merlin uses a Rotax 582, but are they the best option? There seem to be no 4-stroke options in that power range, or am I missing something?

Sprite's yet to be finished Stinger looks a great concept too. Graham kindly sent me some progress photos and it too looks very promising. And, that's designed here, unusual when we seem only to see innovation in the light end from the Czech Republic these days.



Ps, also good to meet the usual suspects like Ian Melville, Brian Hope and Steve Slater hanging around the exhibits and the LAA stand.

Re: Sprite Aviation Merlin

Posted: Sat Dec 05, 2015 12:42 pm
by Ian Melville
Suspect, me? :lol:

I did have a good look at it and a had a chat to Graham, who was helpful regarding my CX4 project. I thought he said that there was a possible 4-stroke in progress for the Merlin? He did quote a name, but it did not sound like the usual suspects(uh oh, them again). I cannot find what I thought he said, so need to wash my ears out. I did wonder if it was this one? as used in the Escapade Kid/TLAC Kub, but that is way down on power compared to a 582 ... es_en.html

I suspect the Merlin will be pushing the top end of the weights and would be very cautious about actual, real world weight. Which makes a 4-stroke even harder to fit. Was very impressed by it though. Pity he will not be importing the tail dragger version when it is completed.

Re: Sprite Aviation Merlin

Posted: Sat Dec 05, 2015 8:45 pm
by Seanjd
I loved it 8)

The tail wheel variant is 10kgs lighter and makes sense to maximise useful weight, plus due to so many people asking about this version, he has decided to offer it now :)

I think the three reserved ready to fly aircraft will be snapped up, and hope the kits sell well. They had a lot of people saying if only it was a 4 stroke! If there is a suitable 4 stroke that is light yet can power this ok, then it should be easy to do. There is a video of early flights with a Verner 35hp engine which sounds like it is a 4 stroke, but I would guess they have chosen the 582 due to its power to weight ratio. The 582 has been around for a good while now, and I think its only negatives are fuel consumtion and low TBO, but there are a few still running well beyond this.
I am sorely tempted I must confess, as it ticks a lot of the requirements I want in an aircraft and the 582 does not worry me unduly. 300 hours is a lot of flying time and as long as you maintain it correctly and look after it in use, as have many of our microlight colleagues before, then all should be well.

On another note but linked to this, why is the limit set to 315kgs if BRS fitted? Surely there is no structural difference of the aircraft so you could safely fly at 315kgs with no BRS fitted! Not that this would be compliant to the ANO, I understand that, but I cannot understand why there is a difference?

Re: Sprite Aviation Merlin

Posted: Sun Dec 06, 2015 4:27 pm
by Ian Melville
Hi Sean,
I saw your 315Kg question elsewhere, Perhaps Flyer Forum?

Because the class of aircraft is limited to 300kg, that does not mean that the aircraft is stressed to this limit. If a manufacture offered a BCAR Section S microlight that took advantage of the extra 15kg allowed BRS, you can bet your bottom dollar that it will meet or exceed the requirements at the higher weight. That was all pre-SSDR of course. Note, I am not saying that SSDRs are no longer analysed for stress, caveat emptor as they say.

The 300Kg limit existed before BRS arrived on the scene. I think the BMAA later made a case for the weight increase to add a safety system. IIRC it was Guy Gratton, who at the time was the CTO of the BMAA. I am surprised he has not responded on the Flyer Forum where he is known to lurk.

Don't think that it can be a sneaky way to gain a few KG of payload :D The BRS unit may weight less than 15Kg, but that excludes any changes to the airframe necessary.

Re: Sprite Aviation Merlin

Posted: Sun Dec 06, 2015 4:52 pm
by Seanjd
Thanks Ian, and yes I did post the same question on Flyer forum but there were a few other posts straight after it, so it probably got missed by those who could respond. :)
I made some enquires on the SkyRanger a while back, and they mentioned gaining a bit of additional carry capacity by having a BRS fitted, but you are correct in that the modification to the airframe to fit a BRS may well use up the allowed 15Kg addition.

If the Merlin had another 10 or 20 kg of use able weight I would have one without hesitation :wink:


Re: Sprite Aviation Merlin

Posted: Mon Dec 07, 2015 9:13 pm
by Ian Melville
You could always go on a diet :lol:

Knowing I wanted an SSDR at some point, I dropped from 210lbs to 175lbs

Re: Sprite Aviation Merlin

Posted: Tue Dec 08, 2015 11:58 pm
by Seanjd
I was planning on losing a few pounds :wink:

The Merlin has given me additional incentive to do so :lol:

Re: Sprite Aviation Merlin 582

Posted: Fri Apr 15, 2016 10:06 am
by longman
My experience of flying my 582 Kitfox is that properly installed maintained and checked, they will give little problems.

I have 1000 + Hrs mostly on 2 strokes with no great issues except for those caused by fuel starvation or ignition faults on the early points engines.

I have worked on many of the lightweight four strokes. None are trouble free. Cams wearing on 912's trashing the engine with debris in the bearings. Jab's with the end busting off the cam, then the oil pump stops ( 3 off ) not to mention props and flywheels coming off.

So I would not Diss the 582. The current one in my Kitfox is approaching 500 hours and it all I have changed are plugs and inlet rubbers.