Jet Provost 1.5metre Andy Blackburn PSS Plan

[Chris Barlow]

That one has come up before Martin. Very impressive!

[Bob Jennings 1]

Oh my word. I’d need a couple of months to get anything close to that!

[Alan Gorham_]

Time for a visit from the scale police....

Lovely though the Strikemaster and it's colour schemes are, it is based on the Jet Provost T.Mk5 airframe which is quite different to the earlier T.3 and T.4 that this plan is closer to.

Look at the fuselage cross sections around the nose and canopy area especially...

[Andy Meade]

nee-naw, nee-naw!

[Alan Gorham_]

Just thought it was worth pointing out.

[Andy Meade]

I think I did point it out a few pages back that there were some nicer schemes on the T5, and no one would care

[Peter Garsden]

Maiden Flight

Today I ventured up the Orme. When I arrived, Andy and Harry were flying up the top as the wind was Southerly. It then suddenly dropped and went South West, blowing 60mph on the edge - only the insane would maiden a PSS model in that wind, but crackers we certainly are.

I had checked the c of g but my Great Planes device always measures too far back. I had added about 2.6 oz to the nose. Before I flew I added another 2 penny weights to the front of the battery.

Andy carefully took it down the slope to the lower platform. I was half way up. He was struggling to hold onto it in the 61mph wind at the compression edge (probably more like 50mph where he was). He let go and the model shot up backwards. I thought it was going to hit the rock so I added a lot of down elevator and it started see sawing. Eventually I got it under control and managed to force it out over the edge. I was holding in a lot of down. I walked backwards up the slope and fell over on the ravine. The JP went up vertically. I recovered and got it under control again. John Hey appeared and I shouted "Down trim as much as you can". He fed in about 3/4 of my available trim equivalent to about 4mm. Finally we were under control. I was being blown back but as long as I kept it far out we were flying but it was hairy. I had real trouble with orientation and there were a few hairy moment. Eventually I got blown back over the slope and I managed to put it down safely. Phew! I was sweating. Crazy to maiden in that wind.

Here I am on one knee, which eventually turned into 2 knees. I couldn't stand up!

Keith and I retreated for a coffee. The wind pushed back to 25mph and swung South. I added 2 more penny weights thinking I could do away with some down trim - wrong...

I ventured up to the South Bowl over the back and had another go. Much better. Wind more suitable, and more weight. Still needs more weight. We found stonking lift over the South Bowl, so we could have some fun...

1. It has much more momentum than the small one, and much more presence in the air.
2. It did some beautiful big loops once I found the lift.
3. The rolls were slow and majestic - very scale.
4. Its whole presence in the air was scale like, much more so than the small one.
5. I think it will fly with good lift in anything from 10mph to 50mph at a push.
6. I was wishing I had used a rudder to help with stall turns which it loves.
7. I flew inverted with not much down elevator.
8. I had to be very ginger adding down elevator and I think it wants to tuck under. I didn't do a dive test. This tells me I need more weight in the nose.
9. I flew it for about 45 minutes (normally only do 15 tops), as I was loving flying it now so much. Definitely a success.
10. I brought it in for a landing from far back over the wall behind, and it just penetrated and landed softly in the grass - says a lot for its penetration.
11. I reduced the throw of the ailerons and elevators by about 15% from that advised on the plan. I increased Expo to 35% which is about right particularly for the elevator.
12. It has been canvassed that the incidence is wrong. I need to point out that there is a building error with the wing fairings which I built flat rather than following the wing dihedral. I think this is altering the wing incidence by about 2mm, which may make all the difference. The trailing edge is not where it should be (too far down which would make it fly slower and nose up!) I am going to alter it then fly again for a true test. I think that is why it was flying slower than the small one. I also think it needs more nose weight. So please don't panic Mr Mannering and alter your angles of incidence just yet.

All in all a brilliant day. Thanks to Harry, Andy, and John for launching, and Keith for the pictures. Here are some videos on You Tube. Not the best but you get the idea.

I am uploading to You Tube but here is one of them that Keith took

[Peter Garsden]

Also

And there are more...

[John A H]

Launch party approaching the slope …...

[Peter Garsden]

There are 2 others but I am sure you will get bored

[Tim Mackey]

Well done Pete on being so quick on the build, first on the build, and doing a maiden in 60 mph wind on the big rock!

 I did venture outside my office and look over, but even at 1.5 plan size didn’t spot ya 😀.

Look forward to getting going on mine sometime👏👏

Edited By Tim Mackey on 03/01/2020 05:11:23

[Phil Cooke]

Congrats on a successful maiden and follow on flights Pete - glad to see the bigger JP idea realised - I think this will prove a popular PSS model!

[Jez Billington]

Well done Pete. Great result. Looks good on the ground and in the air.

[Peter Garsden]

Well, have put the rudder on it now. Will probably be some time before there is an opportunity to fly this properly up the Orme. PSS just stooges around locally and doesn't really fly properly.

I have gone for a ball joint in view of the angle of the snake. I did this on the original JP. I will be cutting off the bolt and applying some Locktite. May also be better the other way up?

You can see the Savox servo added and the various tab additions to the formers to hold the snake, and the support near the servo. It is a free run for the snake.

Also note the way it attaches to the clevis. Conventionally people just apply cyano, but following a tip from Dr. Doc Hammond of Aeroic fame, I also overlay a piece of heat shrink glued into place with 5 minute Epoxy as belt and braces. You don't want one of those coming off mid flight.

[Peter Garsden]

As undertaken to the Scale Police, I have cut down my canopy so it now looks scale (just a wind up - I actually did it because the JP did not fly as fast as the small one which could be down to the rotor forming behind the canopy, so I will experiment with it as is to see if it makes a difference)

The rudder also added a bit of rearward weight so I have added 2 penny weights onto the battery.

A big thanks go out to Chris Barlow who gave me the tip of cutting down the 3D printed pilot seat with a hot knife. Dremmels melt it and cause a mess. I have a gas powered soldering iron which was ideal

I was concerned that we would lose the nice detail at the top of the seat, so I cut a 1/2 inch slice from the top which then lowered the seat nicely for the canopy to be a perfect fit - didn't take long at all and was much easier than I feared.

Before cutting sticking up too high above the pilot's head

And afterwards with the slice taken out and the top lowered.

Canopy back on with the usual rubbery glue. Trim was needed at the rear because the canopy now sits further down and forward.

Just waiting for a suitable trip to Orme to retest it.

Edited By Peter Garsden on 15/01/2020 12:24:54

[Bob Jennings 1]

Well done Pete. Look forward to seeing it off the slope in its slimmer guise!

[Jez Billington]

Nice job Pete. Doing the covering job on mine right now - will share images when done. 
Martin: I like the reptile-like Strikemaster scheme, but it’s well beyond the time allocation I’d give myself to cover a model. I don’t want to run out of steam at such a late stage of the build!

Edited By Jez Billington on 15/01/2020 18:47:43

[Jez Billington]

Finally managed a dry assembly today. Revealed a lot of small jobs that I thought I had already fixed - plus some new ones thrown in. It’s not a true scale colour scheme, but at least I should see it. Thanks to Andy for his pilots - super 3D print job. Chickened our of painting the fuz and used film instead - but it still took some doing. Not far away from a test flight now. Any volunteers to lob it?

[Jez Billington]

H

Edited By Jez Billington on 26/01/2020 18:23:09

[Jez Billington]

all photos uploaded end up upside down. No matter what i try to fix, they always appear that way. Any ideas?

[Peter Garsden]

I think the problem comes when you take portrait instead of landscape pictures Jez. I think the programme automatically rotates them, then you can't adjust them. I had the same problem and couldn't resolve it until I started taking all landscape versions. There isn't an image editing program incorporated into the software. As Tim M will tell you, its very old ASP programming.

[Jez Billington]

Thanks Pete. You're right - this forum platform needs pensioning off!

[Peter Garsden]

STOP PRESS

Re the Jet Provost 57 inch wingspan. The plan and woodpack are now available online via the PSS website here **LINK**

[Peter Garsden]

This post derives from a PSSA event at the Orme last weekend - 11th and 12th July 2020. Whilst I misguidedly did not take my JP because I didn't think we would have the wind to fly it (stupidly as it turned out), post lock down, there were 2 JP's being maidened from Jez Billington and Stevie Kemp.

Jez launched his from the North West slope near the "Rest and Be Thankful!" Cafe in winds varying from 10 to 17mph, but reasonable lift. He had balanced his according to the C of G on the plan. He had a very nerve wracking flight owing to the model being too tail heavy. Due to Jez's outstanding pilot skills he managed to rescue it from disaster and land safely. Panic can easily set in when this happens over the sea leading to a watery grave and a fortuitous gift to a sloper in Ireland.

To be fair, the lift was not brilliant but should have been enough for the JP. Needless to say Jez didn't fly again.

The following day (Sunday), there was no wind until about 1.30pm when suddenly, out of nowhere a 22 to 25 mph appeared for the South West and we had some amazing flying. Most models flew other than those that need a gail.

We all bullied Stevie Kemp to maiden his silver and fluorescent orange version. It was superbly finished as are all Steve's models. He was apprehensive, I think because of what I had said about my maiden, weight, and Jez's tail heavy experience. I think he thought that it needed more wind. He was persuaded to give it a heave ho. First of all he added 40 grams to the nose which pushed the C of G forward from 85mm from the leading edge of the wing to 78mm.

Andy Meade launched it and it sailed away perfectly. Steve was delighted and relieved that it flew in equal measure.

So the lesson is that the C of G for any other builders should be set at 78mm rather than 85mm.

Edited By Peter Garsden on 17/07/2020 13:55:50

[Andy Blackburn]

Well, this is - frankly - shocking. One just can't get the staff.

My apologies to Jez for the unnecessary excitement. I'll make the appropriate changes to the CAD files and re-issue the plan to Phil. It'll take me a week or so because I have my hands full at the moment...

A.

P.S.

Pete - you built the first JP, did yours need the c.g. moving forwards as well?...