Graham Davies 3
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Posts posted by Graham Davies 3
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One note about the Hobbywing ESCs. The genuine ones are fine, but I had a counterfeit one from Ebay and it didn't work! Fortunately, from the outset and I got a full refund. But as with hookie servos, take care.
I've realised now that I have to stop trying to save money as it was costing me a fortune!
Graham
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46 minutes ago, Ron Gray said:
See you there Graham and don’t forget the ‘Laser Day’ and ‘Best of British’ weekend at Bucko in September.
I'll be wearing a carnation and carrying a copy of the Guardian...
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Not for me Ron. I'll go to Modelair at Old Warden and take my grandson round the museum. That'll be me for the year!
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On 15/12/2023 at 15:15, Ron Gray said:
It’s still showing as 23rd/24th June 2024.
Yes Ron, but it's no longer at North Weald, but Lutterworth.
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29 minutes ago, martin collins 1 said:
Taking depron/foam building to another level Graham, do you have any build pictures you can post up? Looking forward to some flight video.
I have a few. Attached here.
If anyone wants any details, I'm always happy to chat through what I did, how I got there and what my thought processes are!
Graham
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Thank you both! Let's hope I can remember how to fly, or even remember my way to the strip...
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Right, she's ready*
1/6 scale spitfire Mk1; P9374. This is a replica (let's not be too eager and call it 'scale'!) of the aircraft that crashed on it's second operation onto the beach at Calais and remained there until the 1980s before being removed and eventually renovated to flying condition. This is detailed in a wonderful book kindly given to me by Peter Miller. As happens with me, reading the book (and particularly John Romaine's pilot notes of the maiden flight) inspired me, and I was 'locked on'.
This is the latest evolution of my learnings of how to make use of Depron. Particularly laminate flooring under floor insulation. This is sold by B&Q under the Diall brand in white in 3 and 6mm and their own brand in black at 6mm. The construction uses some ply and balsa to put strength where it's needed (a hard structure between wing root and motor mount), and B&Q 6mm square strip wood for the wing spars. It has flaps, retracts and Oleos and is set up with a 5065 320kv motor on 6S and currently spinning a 17x8 prop. I'm yet to do the full power checks, so not sure what the output is, but expect around 900-1000W. The battery (3300maH) sits vertically behind the motor, and it looks to balance without ballast. AUW is 8lb. As this model is 74", this is very light. It's the same size as Mick Reeves' Mk9, which apparently fly very well, and usually come in at around 12lb plus. Jon from Laser reckons this is the correct weight, so I may have to stake it down to stop it floating off! In any case, I should get a nice scale speed.
It's covered in 25gsm glass cloth applied with B&Q water based varnish. Paint is good old valspar (again, B&Q) matchpot emulsion matched to the book. It's a tiny bit light, but the effect is good. This is sprayed with my little HVLP gun, and then sprayed over with a light coat of gloss varnish to give a slight sheen for the vinyl to adhere to. Vinyl, canopy, decals and the wonderful dash are all from Mick Reeves. The exhausts are 3D printed.
*Some detailing to do, electrical checks, a lot of worrying, and purchase of bike clips notwithstanding...
Graham
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Thanks all.
Jon, I was hoping you'd pipe in! Thanks for that. I think it's a good point to take performance over appearance, particularly early doors. And I agree that APC are ALL performance. I'll get one on order..
Graham
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Evening all,
Getting towards the denouement of my build. It's a scratch build 1/6 scale (74") Mk1 spitfire based on P9374, which was dug out of the calais sand and restored to flying. It's scale-ish and won't win any competitions, but looks pretty good. I'm new to this scale with my models up to now being smaller.At this size, I keep running into new issues to solve, and today's relates to propellers...
I have 16x8 master airscrew scimitar in my stock, and according to e-calc, this should be just about OK on my chosen motor (5065 320kv on 6S), but ideally I need a 17 or 18x8. I'm not ooking for scale diameter (unlikely) or 3 blades (I've already cut the spinner!), but what props would you as the great and good suggest? I can find precious few at this size that are not either wooden or APC, which look silly. Wooden is a risk on our strip and nose-overs are a real possibility.
What do you suggest, and where would I get them from?
Thanks all
Graham
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4 hours ago, concept2 said:
Hi All..
Sorry for the slight hijack… is this 5mm foam from B and Q suitable for our models, and laser cutting?
thanks
chris
Yes Chris, this is made from mostly the same stuff
Graham
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Some more progress on the 1/6 scale B&Q laminate flooring underlay foam spitfire. Snappy title, don't you think?
This is modelled on P9374 which is the subject of a fabulous book Peter Miller generously gave me. This is an aeroplane that crashed on a Calais beach in 1940 before being excavated in the 80s and restored to flight.
She's not far off now. Some more finishing to bring her to life, and a few bits and pieces such as the battery hatch and gear doors, and she's all but ready.
Some details for you all:
- Built from 6mm (black) and 3mm (white) foam underlay. Depron, or near enough to. And a smattering of plywood, lightply and balsa.
- It will (hopefully) fly on a 3300 6S pack turning something like a 16x10 prop. Still to be defined.
- Covered in 25gsm glass cloth applied using B&Q water based varnish
- Paint is emulsion. The colours are from B&Q's valspar mixing service where they scan your colour and match to it. Both brown and green are a little light, but not bad.
- Parts such as the canopy, decals and the lovely dash kit are all from Mick Reeves. The scale is identical to his Mk9 kit, so they are close, but not perfect.
- She has flaps and retracts, complete with oleos. Thanks to EdgeTX's flexibility, I even have staggered retraction!
- At 74" span, final weight looks like it will be around the 8lb mark. Given that Mick Reeves' spitfires fly very well at 13lb, I'm hopeful...
I think we're coming a long way with foam construction...
Graham
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Thanks Jon, that's really helpful.
The trouble with scratch building is EVERYTHING is a guess. So far, I'm usually not far off, but I am very aware of the balance of CG/ elevator sensitivity/ noseovers!
My Spit is a Mk1, and at 74" will weigh around 8lb, so very light. That does make a lot of things easier, but can also lead to undesirables, such as the temptation to get off the ground too soon. All should be well if I remain patient, and stick to the processes.
Good advice about the flaps. I'm not familiar enough with my TX to modify the mix during flight, but I will set up a couple of mix options on a switch to keep me out of trouble. Again, the light weight may be my friend here. I will check them at height, and if it points to the ground I can recover and try again with an alternative mix. I do have a couple of flap settings already, so I should be able to keep it manageable.
I have a fixed tailwheel. Taxiing is all but impossible on our strip, so I usually try to make the take off a bit easier...
Graham
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On 04/01/2024 at 08:46, Jon - Laser Engines said:
Again as discussed yesterday, a minimum of elevator travel will mean that even if the c/g is a little on the lively side its not going to matter. Excess rates are usually a far bigger problem than a c/g that is slightly out.
Hi Jon,
Completely agree about low rates being the way to go. Quick question though; what do you start with? I'm coming to the end of a scratchbuild 1/6 scale spitfire. My first time at this scale. For a 74" span spit, what elevator and aileron rates would you start with on low and higH?
Cheers!
Graham
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Hi David,
There's various things likely to be affected:
- Wing loading decreases, which lowers your stall speed
- Weight/ drag will increase (I think only slightly though, drag more than weight). Increased drag = reduced speed. Increase weight = increased stalls speed, lower rate of climb etc
- Increased span will reduce your roll rate
- Increasing span will increase the aspect ratio. This may improve aileron efficiency, if they were fitted!
- Increased wing area does (as you rightly point out) reduce the relative tailplane area. This will affect the longitudinal stability and may affect ideal CG position (may move it forward IIRC). However, I think the amount you are proposing to increase the wing would not make a big difference.
Would I increase the wing area? Only if I could do it for zero net weight gain. I agree with Chris; the disciplines of the Coup really favour light weight over a slow stall. You're going to need what speed you can get, so you don't really want additional drag. If you were to get really clever, use a thinner wing section AND increased area!
I think for me though, I'd spend my time reducing the wight and retain the dimensions. I think you risk unwanted consequences (such as you found by reducing the dihedral; you probably lost a lot of roll authority, which is the last thing you needed).
I hope that helps!
G
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Happy new year all.
Made a bit of progress on the Mk1 Spitfire in fits and starts over the holidays. It's pretty much ready to paint, once I knock up a battery hatch. Then paint the pilot and fit out the cockpit, and start fretting about the maiden...
For those that missed the last post (or indeed my others where I witter on about foam scale models...), this is modelled on P9374 Mk1 spitfire that was restored after spending 40 years buried in a Calais beach. The model is made from 6mm and 3mm depron in the form of B&Q laminate flooring underlay. There is judicious use of balsa, light ply and ply where needed. It's a full-fat flaps and retracts model and is 1/6 scale at 74" span (to make use of accessories and finishing parts from Mick Reeves). As you see it, all servos are fitted and apart from the lack of paint, pilot and canopy, and the fact there is a 4S rather than the 6S battery it will fly on, it comes in at 7 1/2 pounds. Given that the Mick Reeves build is generally acknowledged as an excellent flyer at 12+ lbs, it should go OK.
I'll keep you posted as the paint gows on...
Graham
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Second that. Nearly finished mine. Fascinating read...
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42 minutes ago, Graham R said:
A new Christmas read. I'm surprised that the Hurricane hasn't been mentioned. It was the workhorse of the BOB.
You're not the only Graham that got this book for Christmas! Fantastic read, and I'm locked-on to build a Hurri now...
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Trust me Chris, you'll use it! As Eric said, it's highly addictive as you can easily model from very basic information. If I could only get a tiny bit more info on Dick Dastardly's biplane...
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BTW, you'll not need much from your original plan! Just the overall outlines. Shout if you need help or a starting suggestion...
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Chris, you could definitely build either scales from depron. The smaller one would build very quickly and easily in B&Q (diall) 3mm laminate floor insulation, and at that size will need very little in the way of spars etc, so the weight will be very low. I reckon £10 is too much!
Great subject, and a canopy ideal for a coke bottle!
Graham
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Hi Andy,
Might be a bit late now, but I can certainly talk you through what I have done. I have done some build stuff one some of my other foam builds, such as the Regianne Re2005, which flies brilliantly.
It's worth persevering Andy. As long as you put strength where it's needed, and learn a few new techniques, you can create great, lightweight and cheap models.
Drop me a line if you want to chat
Graham
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43 minutes ago, Mike T said:
A few days ago I typed a huge screed re twins and lost the exsanguinating lot when the forum timed out on me before I pressed 'submit'. I'm not going to do it again, so - quick and dirty:
- Sleek, simple twins are best because they have less complicated airframes (e.g. Mossie 'in', Black Widow 'out') This still gives plenty of scope e.g. Whirlwind, Beaufighter/fort, Petlyakov PE2, Mitchell, Marauder, Hudson, DC3, etc.
- No u/c. You can build a model large enough to have some 'presence' but is still easy to hand launch (either self or helper) and can belly land without incident.
and this is the biggie:
- capitalise on the widespread availability of (what I call) the 'standard' sport electric set up - 11 x 5-8" prop. 35XX 900-1200kv motor, 40/60 A ESC and 2200-3000 3S LiPo. Pretty much everybody must have this kind of set up in their stash - at the lower end of the ranges I mention, it's the standard set up in the Wot 4 foam-e. I've got several 🙂
The problem with most twins available today is that they are either too small (using Speed 480-size motors) or too large (using 55XX series motors and associated kit, which is an order of magnitude more expensive that the Wot 4 gear - TN's Mossie a case in point).
Designing around the Wot 4/Riot power train plays to people who already have the gear and results in a twin (or more...) worth building.
My 2c...
Like this you mean?
60" span, fling and flop, 3536 1200kv motors turning 9x5 props on 2200 3S packs...
Graham
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A low stall speed is key. My Cambrian spitfire ate props for breakfast. I'm sure it could get through two per flight. One reason was the speed it came in at. You couldn't dot it down at the point of stall, as it's flight speed range was quite narrow. It also had very little 'lower fuselage' below the thrustline, so nothing to absorb a bit of energy before the prop touched. It's the only 'fling and flop' model I've had that broke props. Generally, it's not something I ever worry about.
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My big winter project is reaching the 'exciting' stage!
74" span (1/6scale) Spitfire Mk1. This will be based on P9374, which was the subject of a book Peter Miller very kindly gave me. It crashed onto the beach in Calais in 1940, and sank into the sand. It was recovered in the 80s, and rebuilt to flying condition. I love a back-story, so this had to be done.
It's mostly depron (laminate flooring underlay from B&Q), but with some balsa and ply in order to keep it all into line at this scale. It is a proper 'full fat' model with retracts and flaps, and a reasonable amount of scale detail, thanks to Mick Reeves. It's (hopefully) going to fly on 6S, and will be covered in glass cloth, applied with B&Q water based varnish (I am not affiliated with B&Q, other DIY stores exist... ;-)). It will be painted with emulsion, and finished in the Richard Wills school of scale. It is intended to look great in the air, good on the ground at 10 ft, and only certain angles permitted to view closer than that....
Target weight is around 7 lb. Given that Mick Reeves superb kits fly incredibly well at 12lb plus, this should get up OK. In fact, as Richard puts it, it may be at risk of flying like a bin bag in any sort of wind... However, it's several hundred meters from the car park to our strip, and I'm gonna need several tea breaks carrying a 12lb model that far.
The thing to note here is how versatile foam/ foamboard/ depron can be. From others on here we have very quick build/ low cost models that take the (financial) fear out of flying and allow us to just enjoy, but it's also possible to make decent and very practical scale models.
I'm always up for a chat about this if anyone is getting interested. Just as an appetiser, prior to my WR FW190 build, I'm going to make a 'Dusty Crophopper' from the Disney film 'Planes' (a great watch, btw!) as my grandson is obsessed with this...
Graham
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Forum members' new models: Let's see them.
in All Things Model Flying
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Maiden flight today. The big foam spitfire flew!
Off the ground in 30ft, gentle climb out and flew like a big trainer. Once my vice grip is relieved on the sticks, I'll be getting to know this big beutiful lump of underfloor insulation!
Graham