Mick Reeves Gangster 63 Lite

[Jonathan M]

As self-prophesied(!), I sealed and then re-did the cowling attachment screw positions on the fuselage for a better alignment with the spinner, then sealed the exposed edges with medium CA to prevent future lifting of the cloth off the plastic.  Ready now for painting in the same brown to match the film.

 

 

Then glued on the canopy with canopy glue - when this is dry I'll scalpel to shape 1/4" strips of the brown film and iron on to cover the join areas as a complete 'framework'.

 

[Jonathan M]

It's finally finished!  Yay! ?

 

Empty weight is 81oz (5.06lbs) so a wing-loading of about 16oz/sqft, which still keeps it in the 'Lite' category of things.

 

I expect the Irvine 46 to pull it around nicely - assuming a peak power output of 875 watts, that's about 175 watts/lb.

 

CG now at 3.75" (95mm) which seems like a safe enough position until I get used to flying it.

 

Thanks to all who've contributed and advised! ?

 

Jon

 

 

 

 

 

 

Edited December 5, 2021 by Jonathan M

[Jonathan M]

I've just realised - looking at my own photos - that I meant to paint the switch brown as well!

 

Does that mean it's still not yet finished?! ? ?

[RedBaron]

The Egyptians always left their structures slightly incomplete for fear that perfection might annoy the Gods with unpredictable results.

[Jonathan M]

2 hours ago, RedBaron said:

The Egyptians always left their structures slightly incomplete for fear that perfection might annoy the Gods with unpredictable results.

 

From an ancient Egyptian RC forum post...

 

[Murat Kece 1]

21 hours ago, Jonathan M said:

It's finally finished!  Yay! ?

 

Empty weight is 81oz (5.06lbs) so a wing-loading of about 16oz/sqft, which still keeps it in the 'Lite' category of things.

 

I expect the Irvine 46 to pull it around nicely - assuming a peak power output of 875 watts, that's about 175 watts/lb.

 

CG now at 3.75" (95mm) which seems like a safe enough position until I get used to flying it.

 

Thanks to all who've contributed and advised! ?

 

Jon

 

 

 

 

 

 

Excellent.. Very handsome.. Despite the unpainted switch?

[Piers Bowlan]

I like the scheme Jonathan, well finished. Good luck with the maiden.

?

[Jonathan M]

Thanks Piers (& Murat).

 

Maiden now just of question of waiting for the rain to stop falling (see hieroglyph above) and wind to stop blowing so hard, and cloud base to push up a bit, etc!

[Paul De Tourtoulon]

.46 is more than enough my one in the 70's had an HP .40 in it,,,

[Jonathan M]

Hooray!  Maidened!  Yes it was cold, damp and quite blowy, but was free after lunch so went up to the patch.

 

The old Irvine 46 on an 11x6 prop started easily and ran very nicely (2,500 idle up to 11,000rpm with a reasonably smooth take-up, can finesse it later), but the noise was quite 'tinny'... I think from the cowling.

 

Ground handling was fine with the steerable nose-wheel, although the strength of the gusts when taxying downwind complicated things a bit until I worked it out.

 

Needed only a tad of aileron trim, but a good couple of mm of up elevator in the air, which surprised me as the CG is at a good 3.75", but maybe that was due to the full (10oz) tank?  (There's only a washer's thickness of right-thrust and no down, so it can't be that.)

 

Didn't really have much opportunity to run through the usual range of manoeuvres and trim/travel/expo checks with any comfort, as the wind, slope-lift and turbulence wasn't exactly conducive - although it seems to have plenty enough power, looped and rolled quite nicely and inverted didn't need too much forward pressure on the stick - and I was anxious to practice a couple of power-on landings in case I had a dead-stick.  

 

So after four or five minutes I lined up and came in.  Landing wasn't the best - a bit of a bounce at first (I blame the conditions!) but she then seemed to came down nicely enough - except then settled to a stop with one wingtip resting on the ground!

 

Seems like good old Mick Reeves got in his revenge at the end!  The saddle-clamps on the right wing U/C had simply shattered on first contact and the wire just folded back!  One of the clamps also broke on the other wing but at least that U/C held.  I've only got a set of larger clamps for 8 SWG, but these by comparison are nicely plastic with plenty of strength/give, with none of the brittleness of the originals.  (I could fit these and bulk up the wire with say tape or alu tubing, but prefer to do to a proper job so have ordered two packs of the same brand for 10 SWG wire.)

 

Nonetheless, very chuffed to have finally flown the Gangster - and looking forward to much more!  ?

 

 

 

 

[Andy Stephenson]

Jonathan,

 

Looking good, glad to hear you maidened your Gangster, now you have a good model to practice for your B with.

You could make up some ali clamps if you are going to fly in such arctic conditions as plastic gets brittle at these temperatures.

[Peter Jenkins]

Well done Jonathan.  You have a great aircraft there for the B.  The key to passing the B is practice and more practice!  

[Nigel R]

great stuff jonathan ?

 

U/C sounds like a part of 'first flight trials'

[Jonathan M]

Thanks chaps!  It's fun this hobby, innit?

 

Interesting Andy that it could have been the cold that made the clamps brittle.  The old ones and the new but oversize 8 SWG ones are both at the same temperature in my heated workroom, so off now to do a bit of laboratory-grade destruction testing...! 

[Jonathan M]

Out again today and I'm really loving this!  First time I've flown any trad power aerobatic model that feels just so right!

 

The replacement saddle-clamps coped fine with multiple landings, but it frankly needs bigger wheels as the 2" supplied ones trip all over the place (I've got a set of 3" DuBro low-bouncers but 2.75" would be better - either option means bending up new 4mm wires for the rear U/C).  Found that full-up elevator helps take the pressure off the nose-wheel when turning on the ground.

 

Wing tip opposite the sidewinder's cylinder head needed 5g of weight to balance.  The CG at 3.75" still needs at least a mm of up elevator so pulls gently towards the canopy in a power-off vertical dive - will move back say another 1/4".

 

Finding that the initial book settings are mostly spot on:

• Elevator +/- 11mm (book says 12mm) with 25% expo (still fine-tuning);
• Ailerons at +/- 18mm (same as book) with 20% expo seems to give a good roll-rate (for me);
• Rudder at +/- 50mm (book says 35mm) with 20% expo.

Rolls are very close to axial with no differential dialed in (yet).

 

Very neutral at stall so needs clear rudder to instigate spin, but snaps out of it immediately and accurately as soon as the controls are centred.

 

Stall-turns need a blip of throttle to help get the rudder over (and/or I need to learn to yaw over before the airflow dies away completely?) but are otherwise completely clean with none of the tail-wagging flip-flopping of the Wot 4.

 

The old Irvine 46 (with its new baffled muffler) gives almost unlimited verticals - more than enough!

 

The 10oz tank I fitted (kit came with a 12oz version) gives an easy 12 mins with plenty to spare (say up to 15-16 mins).

 

All we need are more calm weather days - forecast for next week looking more hopeful! ?

 

Jon

 

 

[Jonathan M]

Interestingly a mate sent me a flying spec for the original Gangster 63:

• 5.75lbs (15% heavier than my 5lb Lite)
• Enya 60 with an 11x7.5 (that's coarse and fast, mine is an 11x6)
• CG at 110mm (mine's currently at 95mm, going to try 100mm next - but only if it needs it)
• 1° of down-thrust, 3° of right (mine was no down, 1° right - but I've just now shimmed it out to give 2° right as I think initial tests showed a tendency to still roll a bit left when the power comes on).

Jon

 

PS - Hope I'm not boring the parish by going on and on!!  Just that I'd like it if anyone else who decides to build a Gangster Lite can benefit from what I've learnt etc.

 

[Jonathan M]

Got to use my patent wire-bender for the first time ever making new 8 gauge U/C for the new 2.75" wheels (with a bigger internal diameter than the original smaller 10 gauge ones).  Quickly discovered that the trick was to hold the first bend (axle) flat on the plate to ensure an accurate parallel second bend:

 

 

And a similar dodge for the final bend which is at 90° to the rest:

 

 

This all now looks like it'll cope with our patch much better:

 

 

Needless to say weight crept up by 5oz (from 5.1 to 5.4lbs) and there'll be a tad more drag, but can live with all this:

 

 

Turns out that the heavier gear didn't change the CG at all, which is still at 3.75".  But while it was on the stand I experimented with adding 10g weights to the tail and noted how much the CG moved aft - 1/8" (3mm) each time - which would be helpful for my next flying tests at the patch:

 

 

 

 

 

 

Edited December 14, 2021 by Jonathan M

[Peter Jenkins]

Jon

 

Well done on the wire bending.  Looks very professional.

 

Also, good prep for the calibrating the weight and CG movement issue.  It will come in handy I'm sure.

 

Peter

[Jonathan M]

After several sessions of trim flights over the last week, this is where my Gangster is now at:

As built and first flown, the model needed a good amount of up elevator.  But before going large with tail weights to move the CG aft etc, I fished out my incidence meter which showed that the wing had a default incidence of almost 1° negative!  

 

So I made up two pairs of temporary hardboard and MDF shims (could eventually use lite-ply but wanted a quick method for initial tests) to fit between the wing and the rear mounting-plate with holes for the nylon screws:  two at 2.2mm thick each and the other two at 2.9mm each.  Combined in pairs, these give a total thickness of 4.4mm, 5.1mm and 5.8mm, resulting in positive incidences of 0.2°, 0.5° and 0.8°.

 

Not having previously - methodically - set up and fine-trimmed a proper aerobatic model, I printed out the GBRCAA Trimming Chart and worked through this repeatedly on several series of short flights (half-tanks of fuel to keep the nose light), at each of the 0.2°, 0.5° and 0.8° wing incidences.

 

Straight & level flight revealed a need for slight right aileron trim (there's a very slight warp in the right wing resulting in a tad of wash-in), while the as-built 0° down-thrust was perfect.  Other tests on the chart showed a need to increase right thrust from 1 to 2°, and lateral balance was achieved by sticking a 10g weight on the left wing-tip (i.e. opposite the sidewinder engine cylinder).  Aileron differential I'm still fine-tuning (it doesn't seem to need much if any) and my rates are currently set for a complete roll-rate of 2 secs.  Both aileron and rudder have 20% expo (rudder can probably use less).

 

Which just left the two usual suspects of CG and wing-incidence to deal with (with elevator rates to suit!).  But, while these are separate issues, I found it quite tricky in practice to juggle the tests, make incidence, tail-weight and elevator trim/rate changes (one at a time) and interpret the results correctly without getting confused!

 

But the net result of all these methodical tests has left me with (aside from a knackered brain, a bad back and a week's worth of stubble!) a working result of:

• 0.8° wing incidence
• CG at 4-1/4" (108mm) via 40g of tail weight
• very slight down trim on the elevator (travel range of +7/-8mm on 30% expo)

At these settings:

• incidence test (gain height, vertical dive at idle) remains vertical ?
• CG test (both versions: 45° down-line on half-throttle and 45° inverted up-line on full-throttle) gives only the slightest arc towards the canopy ?

I'm now finding the Gangster a dream to fly.  It goes precisely where I want to put it, and accelerates and decelerates with the Irvine 46 (11x6 prop) exactly as needed.  Stalling on full up elevator for spinning produces a good amount of nodding before it eventually falls off (usually to the right) but clear rudder input works immediately to instigate spin and neutralising it gives instant and accurate heading recovery.  Inverted flying is very comfortable and assured with only a very slight forward pressure on the stick.  Landings are consistently accurate (touchdowns within 10m of chosen spot) sometimes a three-pointer, sometimes on main UC before dropping onto nose-wheel, but without any worry of dropping a wing in whatever conditions of wind speed and direction.

 

Happy Chappy ?

 

PS - just taken delivery of a good Irvine 53 from a bloke giving up  IC.... ?

 

[Peter Jenkins]

Woo hoo.  Well done Jonathan.  Sounds like you are almost there.  I say almost, as I would fit the Irvine 53 immediately.  You can never have too much power in an aerobatic model as you can then just use half throttle for straight and level and use the excess power to try to achieve near constant airspeed regardless of aircraft attitude.  Constant airspeed has the advantages of:

• the aircraft is always at its trimmed speed so will always be in trim, whereas slowing down will show up minor faults which you will need to correct if you are to maintain the required geometry of the manoeuvre
• the radius of a loop will be easier to maintain as speed determines the radius of turn.  Slow down and the loop tightens unless you take to pushing down elevator to try and maintain the loop diameter
• control response will remain constant as the airspeed over the controls will be constant.

Plus, it all looks better and, from the pilots' viewpoint, it's a bit easier to fly the manoeuvre.

 

Have even more fun when you have the Irvine 53 in place.  Note that the 53 is lighter than the 46, as it's the same crankcase but bored and stroked, so you might need to check the CG once the 53 is installed.  Oh, does your 53 have a silver or black carb.  Silver is the last version and it was significantly more powerful than the preceding version with the black carb.  Both are good but the later version is better!

[Andy Stephenson]

The 53 is only a few grams lighter than the 46 so it shouldn't make any noticeable difference to the trim.

I have to say Jonathan, you have gone much further than I did in trimming for aerobatics. May be I should try harder then I might score more points in the UKCAA contests.

 

http://www.ukcaa.org.uk/

[Jonathan M]

Thanks Peter and Andy

 

Peter, I appreciate the advice on fitting the 53 and now understand from that the reasons why.  Yes it has the silver carb (as does the current 47).  The guy I bought it from was using it to pull around an Acrowot with a 12x6 prop, says an 11x7 also works well.  With the slightly bigger wheels now on my Gangster I should have clearance for the 12x6, which should also be the quieter of the two.

 

Andy, trimming will probably prove to be the easy part, because that was just a question of studying the theory and then being methodical with each component part almost every day over a week.  Whereas practicing flying any given schedule - without hesitation, deviation or repetition - that will really test me!!

 

To be honest I have little interest in just pottering a powered model around the sky.  But more to the point I repeatedly became frustrated with my previous attempts to make any progress with traditional aeros.  In part this was because I was trying to improve my skills by flying less than suitable models (after learning with a Riot, I then had an ARTF Acrowot with a 70FS which unfortunately splintered into hundreds of pieces early on in its life when my then Spektrum TX failed, then an ARTF Wot4 first on electric then with a 40, also an ARTF Boomerang with a 46), but also because I didn't really understand how to set them up optimally in the first place.

 

Building the Gangster has been a bit of a journey (to say the least!) but I learnt a huge amount in the process.  And on its first few flights, even before fine-tuning the trim, it was immediately clear that it was such a different beast to the other models.

 

I have an Acrowot kit to build one day for the 70FS or a Laser 80, but my next power-build (some time in 2022?) is likely to be the Chilli Breeze for an OS35AX - 2/3rds the size of the Gangster but a not dissimilar type of model - and at least I'll be working off a proper plan and proper magazine article.

 

Cheers

Jon

[Peter Jenkins]

Jonathan

 

Once you get used to flying the Gangster, you will find the Acrowot a disappointment.  It is simply not in the same league despite it being a very popular club aerobatic aircraft.  It has too many bad flying features that you will find will hold your aerobatic progress back.  You are just finding out the difference between a proper aerobatic design and others.  You would do better to build one of the 60 size classic aerobatic airframes such as the PB Bullet.  Sadly, there aren't any plans for modern day designs that you can build as a kit.  There are some in the USA but then you have the aggravation of shipping costs across the pond and duty and VAT to pay on top.  Just thought I'd flag up the issue with the Acrowot.

 

By the way, I've just bought a Wots Wot that was built yonks ago and is rather heavy.  An OS61FX was not man enough to give a decent vertical performance despite propping it to allow 12,000 rpm static on the ground.  It now has an OS91FX in it and although it is still being run in, the increase in power is looking promising.  Currently it's turning a 14*10 APC as I didn't have the recommended 15*8.  That gives 8,500 rpm so I guess that if I fit a prop that will allow 10,000 rpm static it might allow the vertical speed to match horizontal speed at half throttle.  Like the Wot 4 and Acrowot, the rudder on the Wots Wot gives an immediate yaw and bank.  This is not something that a proper aerobatic design would support.  So, a touch of mixing opposite aileron will be needed to allow rudder correction to be made, and even the use of rudder in rolls, without having the roll rate slow down and speed up as rudder is used.

 

Cheers

 

Peter

[Andy Stephenson]

Peter the PB Bullet is a 40 size plane, I built one a couple of years ago but it's a bit too fast for comps. Maybe you are thinking of the PB Tornado. There's also the Calibre MKII which is a scale-up of the Bullet to 60 size. Kits available from Cloud Models.

I also have an Acrowot I built in 1986 with a Laser 75, recently refurbished see my icon. Someone told me that if I took it up really high, with full throttle and no other input than full rudder it would bunt so I tried and it did. Try as I might I couldn't get it to knife-edge, there were just too many control interactions to fight with. It's fun model but it's not one to practice pure aerobatics with.

There are a lot of plans for classic pattern models on the outerzone and on the UKCAA site. They also occasionally crop up on the BMFA classifieds.

[Peter Jenkins]

Andy, you are right of course!  I'm more into today's F3A stuff so am a bit rusty on the classic stuff.  Having said that, I have a kit for a Taurus that I will build one of these days and a Veco 45 to power it!  The Taurus goes back to 1959 so was flown on reeds -  a feat that just amazes me!

 

Agree with your view of Acrowots.  My Wot 4 (Irvine 53 with a throttle pipe) and my Wots Wot are great fun but you spend a lot of time flying them as opposed to flying the manoeuvre!  They are like chalk and cheese when compared with my current and past 2 mtr aerobatic airframes.