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Member postings for Jonathan W

Here is a list of all the postings Jonathan W has made in our forums. Click on a thread name to jump to the thread.

Thread: Irvine 61 new bearings
18/09/2019 22:16:43

That is where the bearing splitter mentioned in the other thread comes in handy. The knife edges of the splitter will get into the small gap between the bearing and the crank web.

18/09/2019 19:49:09

Aye, I'm no longer surprised that I see so many engines with butchered prop drivers and damaged crank threads, when I read the bodges espoused on this and other threads!! Mixed in with some sound good advice of course smiley Nothing works better than the right tools for the job.

Thread: Latest CAA Update
14/09/2019 21:01:56

I'm sure that the nutty professor who sat next to Dave Phipps in the Commons Committee could tell us!

Thread: Irvine .53 / Ugly Stik
14/09/2019 11:31:36

That's a good point from Nigel R on the wing section and reflects my experience of reluctance to spin. Also, I would agree that no dihedral is necessary.

On the engine front, the Enya 60 was a good engine of its time and will only be a little short of power compared to the Irvine 53. The silencers in those days were less restrictive, so that tends to boost the Enya relatively.

The Rival looks good and you could stretch that towards 60" if you wanted to play around with CAD.

Ref the weight of the OS91FX in my 72" Ugly, it's a light engine for its size and weighs 550g, exactly the same weight as the OS61FX (quoted from the OS owners manual). The 72" Ugly has 1000 wing area and is draggy, so it needs the power. I was flying it only yesterday!

13/09/2019 23:42:29
Posted by Denis Watkins on 13/09/2019 23:00:06:

SM, that Irvine could pull 6 - 7lb

So look to guestimate around 66" span

Or use a smaller motor


I have to disagree with this. If my 72" version is good with a 91 engine, I don't see how a 66" version will be adequately powered by a 53. No doubt it would get off the ground, but remember that this particular model has a large wing area (low aspect ratio wing), thick wing section and is very draggy. I would expect 55 to 60" tops to be suitable for the Irvine. But in the end, we all have an opinion, so take your pick!

For another point of reference, another club member powered his 72" Ugly with a 91 4 stroke and said it flew like a trainer, very sedate.

Edit to say...

Looking at the various plans on Outerzone, the original Phil Kraft design was 60" and he typically used an Enya 60, which was a old crossflow engine, although the model would also fly more sedately on a 45. Therefore I would say, go with the original 60" design by Phil Kraft and the Irvine 53 will be spot on. Why mess about scaling up or down when you have a proven plan just the right size?

Edited By Jonathan W on 14/09/2019 00:06:43

13/09/2019 22:28:45

I don't know the exact answer to your question, but I have a 72" Ugly and it's about right with an OS91FX (2 stroke) on a 14x7. It will go vertical not unlimited, but a long way, such that to do stall turns you need to throttle back. Therefore your proposed 55" and engine/prop sounds in the right ball park.

I would advise that the fuselage has very little side area (hence "Stick" and this does limit the aerobatic range. Also, it has a wide chord "barn door" type wing and I find that mine does not spin very well, tends to end up in a slow spiral dive despite the CG being a little to the rear.

That said, it's a good tough hack model that you don't need to be too proud of. It floats in on landings really nicely and is very forgiving.

PS the smiley was accidental, but happens to be about right!

Edited By Jonathan W on 13/09/2019 22:30:27

Thread: Latest CAA Update
06/09/2019 13:59:35
Posted by Steve J on 06/09/2019 13:45:01:
Posted by Erfolg on 06/09/2019 12:19:31:

I found it very disturbing that apparently Local Authorities in Southern England appear to be using quads over private properties in contravention of the 50m rule. Presumably a blind eye is presently been turned with respect to them.

This will be being done by people with PfCO and will be subject to risk assessments etc.


Aye, but how do the people getting annoyed about being over-flown know about the PFCO or risk assessment? Even if the drone in future had EC, are the people underneath supposed to look it up on a smart phone "App" and then realise that they are not entitled to be annoyed?

Edited By Jonathan W on 06/09/2019 14:03:58

Thread: Drones in the news - again...
25/08/2019 03:05:15

It's business as usual. Back when the illegal CB craze was causing problems for RC modellers, the same publisher was producing RC magazines and magazines promoting CB.

15/08/2019 10:35:04

All very well, but what is the justification for a 2 NM radius no fly zone? 1/2 mile would have been enough. As it was, not only were people rightly not allowed to fly at the event at the Hoe, nor were they alowed to fly from land across the other side of both the river esturies.

The flyers were probably breaching the normal restrictions of flying in proximity to people & property anyway, without any no fly zone being imposed.

Thread: Advice needed
14/08/2019 14:17:51

My condolences also Jill.

If you can say what area of the country you are located, this might generate some interest from people local enough to collect the model.

Thread: ASP prop driver stuck!
12/08/2019 17:34:18

Hi Keith,

I should have said before, but was trying to keep the word count down!! Yes, I have experienced a prop driver moving back and locking the engine and this was due to the prop driver splitting from the taper after it was over-tightened (by A.N. Other). In my case, the prop driver was a casting and therefore more brittle than machined aluminium. It had spilt radially all the way out from the taper bore to the outside. Due to being fully split, it had lost much of its strength and pulled off very easily.

This does not appear to exactly be the case with yours. I'm not familiar with the ASP 4 strokes. All mine are OS & Saito. Is the ASP prop driver a casting, or machined from solid? It would be surprising if a driver machined from solid bar had spilt, but then it may be low quality material. Also there could be a fault with the taper collet, if for example it was machined towards the bottom of the tolerance range and had finally allowed the driver to move back just that fraction too much.

Good luck with your task. I'm also a customer of Cromwell tools. Your separator should do the job, so long as you ordered the appropriate size.

Regards, Jonathan

11/08/2019 16:30:59
Posted by Denis Watkins on 11/08/2019 16:14:33:

Yep Bert, Freeze the motor, warm the prop driver, PING, job done

When you are heating the prop driver, what is stopping the heat conducting instantly also into the crankshaft, which is in direct metal-to-metal contact with the prop driver?

According to my understanding of the laws of physics, the crank will not remain at freeing temperature as soon as you apply significant heat to the prop driver.

Certainly, a few heat cycles - heating followed by quenching - might shock it loose by rapid differential expansion/contraction, but I don;t see how it is possible to maintain the crankshaft at a significantly different temperature to prop driver.

11/08/2019 11:01:09

Having looked at the picture in your gallery, the puller is not effective due to the bending of the metal plate you have used to adapt it to the prop driver. I think your best bet would be the bearing separator, as previously suggested by Martin Harris.. I also use a separator and the extra rigidity provided works wonders.

Thread: Commons Science and Technology Committee Enquiry on Drones
05/08/2019 09:28:30

I think the counter point is that the model flyers are being asked to "pick up" for the commercial users' nationwide airspace management system when all we do is fly in small circles around pre-defined locations.

Thread: Old Fuel
29/07/2019 15:25:41

One thing that WILL make fuel go off is using a brass clunk weight on the end of the pick-up pipe dangling down from the bottle top. My dad left a bottle of his like that for a couple of years. The fuel looked like Guinness and the brass looked like something from Roman remains.

I've got a stainless steel clunk in my bottle and it still looks like new after a number of years permanently living in 10% nitro.

Thread: Perry carbs.
16/07/2019 01:30:48

Perry carbs work great when properly looked after, but they are not tolerant of bodge merchants unfortunately. That's where they get a bad rep I think, from people who don't have the patience to keep these carbs sweet.

As previoulsy stated, cleanliness of the fuel supply is essential, so always run a filter. Decades ago, I ran a Veco 19 in a RC car, a very dirty environment. No problem from the carb due to running a filter.

The internal O ring condition is critical.

To inspect, unscrew the needle valve. There should be a spring on the needle. If missing, a ball point pen will probably yield a usable spring which can be cut to length.

Once the needle is out, you should see a small E clip which needs carefully prising off - don't lose it!. You can then extract the throttle barrel and the "reservoir" from either side of the carb body. The "reservoir" is the piece with the brass disc and inside it has the mixture adjusting slot, sealed with 2 O rings. The O rings are a standard BS size: 007 (1.78 x 3.68mm). Most standard O rings are Nitrile material, which won't last long in glow fuel. Try either Viton or EPDM material.

Here is a supplier: Link

Also, try to avoid over-tightening the carb retaining grub screws, otherwise the carb spigot can get crushed or even crack.

If you get frustrated with this carb, I'l have it smiley

Recommended prop for the HB25 is 9x4 or 9x5

Edited By Jonathan W on 16/07/2019 01:48:52

Thread: Commons Science and Technology Committee Enquiry on Drones
10/07/2019 13:00:57

Yes, I was already getting confused by the meaning of UTM, since I have to be aware of the Universal Transverse Mercator coordinate system in my job.

09/07/2019 13:04:37


The Baroness came across as arrogant to me.

I think something was missed by not mentioning that we are recognised as a sport and the benefits of participation to people with not the best physical ability to undertake more energetic activity. The registration scheme as currently proposed presents a barrier to participation, especially to those who already only fly occasionally.

09/07/2019 10:34:13

Missed the first 20 minutes, but crikey! It's hard for anybody to make any sensible points when this mad professor character David Dunn goes off on wild speculation and scare stories about terrorist drones in Yemen.

Thread: Side-thrust and wash-in
15/06/2019 13:14:05

How much wash-in have you got? Unless it is very bad, I doubt that will have too much negative effect given that you have a paralel chord flat bottom wing section and a light wing loading.

I am thinking that maybe you reduced the dihedral too much. The Super 60 is a high wing design, but the Baron is a shoulder wing, so I expect it would need more dihedral. I've once flown a 3ch RET model with too little dihedral and it was pretty horrible, much as you describe, very "tippy". Directiional control with the rudder was poor, due to too little dihedral.

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