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DB Sport and Scale Auster J1 Autocrat


Danny Fenton

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On 08/06/2022 at 18:28, David Ovenden said:

Danny, I regularly fly four stroke powered models as well as electric ones. I am always more nervous test flying a new electric model than one powered by a four stroke engine.

You will be fine I'm sure. Look forward to seeing the photos.

I guess it is horses for courses, I am completely at home with electric, IC seems to be a case of, not will it quit, but when.

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Danny, nearly every model I fly is equipped with a four-stroke engine. If the engine has compression and is fitted with a good glow plug, I use the OS F in everything, and if it's using the recommended fuel, 10%-15% nitro in the case of Saitos, and if it's tuned correctly, there's no reason why the engine should cut out in fight.

 

That said, I have never owned a Saito so don't know anything about the recommended running-in process, but if I have a brand new engine in an airframe, I don't try to gain the absolute maximum revs out of it for the first four or five flights. Neither do I adjust it for the slowest possible tick over until it's had a few flights.

 

 

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I am talking from some experience, I turned to electric back in 2007 because 2 stroke glow, was totally unreliable for me. All the wise sages in the club couldn't figure out why my engines cut. Three different engines, different fuels, props plugs etc. So I hear what you are saying but we will see, I am perhaps just jinxed.

Cheers

Danny

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Wot Ron said!

 

Danny, your Saito is a high quality engine with a reputation for reliability. Ok, the exhaust is non-standard but that is not usually an issue with four-strokes in my experience.

 

With two-strokes on the other hand, they are so simple that everything needs to be pretty well spot on before they'll go. I have seen two-stroke engiines fail to start because the glow plug was the wrong heat range or because the fuel was old or otherwise unsuitable. A change of plug and fuel and away they went.

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2 hours ago, David Davis said:

Wot Ron said!

 

Danny, your Saito is a high quality engine with a reputation for reliability. Ok, the exhaust is non-standard but that is not usually an issue with four-strokes in my experience.

 

With two-strokes on the other hand, they are so simple that everything needs to be pretty well spot on before they'll go. I have seen two-stroke engiines fail to start because the glow plug was the wrong heat range or because the fuel was old or otherwise unsuitable. A change of plug and fuel and away they went.

The two O.S motors a (25 and a 40) and a Jen 57 would start just fine but get a few minutes into a flight and they would go sick and stop ?

Never got to the bottom of it, went electric and never had any further problems.

But I will give it another go, you never know perhaps the jinx has worn off ?

 

Cheers

Danny

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Hi John, yes I appreciate they need cooling, and I am worried about this Auster in that regard, but I have fitted a tight baffle as advised by several modellers, hopefully that will mitigate the risk.

My early experience was with a Wot4, so cooling should not have been an issue. And I tried it with and without the cowl. As I said we tried lots of things. My examiner for my A test was very understanding and still passed me even though I twice went dead stick. The fact that I landed at my feet both times maybe did me a favour ?

 

Anyway lets just see how it goes, I am currently making a flight box and acquiring all the paraphernalia that goes with fuelling and starting.

 

Cheers

Danny

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1 hour ago, David Davis said:

Some engines require a bit of running in Danny.

 

The two O.S's were run in plenty - dozens of flights in a Funfighter (the 25) and dozens of flight in a Gangster 52 Then a Flair Legionnaire (the 40) I have had them since the late 70's The Jen 57 was new, but I ran half a gallon in the garden.

The two OS's ran fine in the 70's It is as if modern fuels disagreed with them. The Jen 57 was a more modern engine designed for modern fuels so should have been fine.

The problems are one of the reasons I am re-visiting glow, its something that has nagged at me.

 

Anyway thank for your thoughts, most enlightening.

 

Cheers

Danny

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I resisted going electric for quite some time but eventually I had to admit that the complete lack of fuss, bother and faff was too compelling. 

 

I would like to see a few scale models and a multi or two in my future and not having to worry about tuning, cleaning, starting, cutting out, idle issues just takes away so many areas of anxiety for me. 

 

In other news, your build here continues to inspire me. That inspiration may take a long time to bear fruit, but nonetheless, reading through this has been an education. 

 

 

 

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I have mounted the Rx battery in the cowl area.

 

838.thumb.jpg.82e08f9a709f5b7ef31f8042b4bf5702.jpg

 

The wires will be tidied up and secured.

 

Now looking at the remote glow connection. I really liked something I think I saw John Rickett using and that was a 3.5mm mini jack, should be meaty enough for 3A at such a low voltage?

 

837.thumb.jpg.41b3fd4a79eed256ab0a478fdce01722.jpg

 

Cheers

Danny

 

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Thanks chaps, that will do me.

 

839.thumb.jpg.7590a0555483a48452cf62c8c0287bd7.jpg

 

I will secure the wiring to stop it flapping. The Allen screw extending the needle valve is only 6mm below the cowl so the head is easy to find thankfully.

 

840.thumb.jpg.7742848f0d817b55286913c77ea06c6e.jpg

 

841.thumb.jpg.da366c5fa302c99ee4fa45fa1de1c6a0.jpg

 

Cowl fit looks poor in these pics, it's not that bad!

 

I fear a session in the garden coming up......

 

Cheers

Danny

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Would appreciate your comments on shortening a crank. To make a blunt spinner that the Auster has there is 6mm too much thread length beyond the prop.

 

20220617_095923.thumb.jpg.a28f011ddc76c1030ada80167ad5f8c2.jpg

 

I think I may make the spinner, to basically see if i can, then cut the shaft after flying the maiden. Assuming you don't tell me not to?

Cheers

Danny

 

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? equivalent to cutting your right arm off!!! definitely would not recommend it, as it has been manufactured to that length for a purpose and it would certainly devalue the engine if you decided to dispose of it.

 

Though it is down to personal choice but why cut a engine up for 6mm, you did say sport scale.

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