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New 78" Vulcan for twin 90mm DF

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Greg Minden29/03/2020 18:29:22
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50 forum posts
37 photos

I too had to do it like Craig said - in pieces. The other way just wouldn't work for me. That done - i kept looking at those flat "air dams" next to the fans and, well you know the rest. Probably uneeded.

PeterF04/04/2020 12:20:03
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525 forum posts
724 photos

Greg,

In my professional life before retiring I was involved in the designed of high velocity fluid flow components and a rounded lip on the entrance to a duct is as good as a shallow cone in keeping flow disturbance to a minimum, both answers are equally as valid.

Craig,

Have you made any further progress on your build.

I have started glassing and have completed the fuselage. This was the stage I was not looking forward to. I have only glassed a plane once and that was 15 years or more ago and it did not turn out very well, it needed a lot of sanding and a lot of high build primer and turned out overweight. It was a DC3, needless to say extra weight on a plane with heavily tapered wings was a bit of a nightmare.

I watched the videos by Danny Fenton "Glassing my Way" and "Hawker Fury Mk1 fuselage glassing" and I have followed those methods using the foam brushes and peel ply. I wish I had seen this years ago because it has been a lot easier than my first attempt and has resulted in a good even lay down of the cloth with good adhesion and very few areas with excess resin. I used West Systems epoxy 105/206 and glass and peel ply from East Coast Fibreglass supplies.

The only thing I have found is that the foam brushes start to break up after a while, perhaps I am too rough with them, having a pack of 20 means I have lots available to keep swapping as soon as any black bits appear on the glass cloth. I have used both resin addition methods, adding it to the surface first then placing the cloth down and placing the cloth on dry then adding the resin. I can not make my mind up which is the best yet, the end result appears to be identical.

Fin and wing join reinforcement panels glassed with peel plydsc08839.jpg

Upper fuselage completed ready for sandingdsc08862.jpg

The majority of the bottom of the fuselage glassed in one mammoth session. This was done in two halves with an overlap on the centre linedsc08852.jpg

First side of the peel ply being removeddsc08857.jpg

Underside of the fuselage completed ready for sandingdsc08866.jpg

Martin McIntosh05/04/2020 20:08:24
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3329 forum posts
1178 photos

Please remind me which fans you are using. I have just blown up the impeller on my Hawk while messing with it on the bench. A loose connector got sucked in! Ordered a new sort of similar one from HK and hope that it fits but it could be a long wait. Current one is 12 blade 10s.

Greg Minden05/04/2020 21:00:19
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50 forum posts
37 photos

Martin - I don't know who you were asking but i am using Jet Fan 90s with HET motors on 10s. (9 blade)

PeterF05/04/2020 21:11:37
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525 forum posts
724 photos

Martin,

The fans are from Exreme RC in Australia with 90mm machined alloy shrouds fitted with Ejet Jetfan 90mm 9 blade rotors and HET 650-68-1600 motors. On 8S they should pull about 100A and give 4.5kg thrust.

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Martin McIntosh05/04/2020 22:48:11
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3329 forum posts
1178 photos

Thanks both.

patrick mcateer12/04/2020 14:58:09
6 forum posts

hello Peterf, ive tried to pm you for the file but its not letting me. i think your doing a brill job there and its help me loads as im building the same as vulcan as you.

keep up the great work

PeterF12/04/2020 19:53:08
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525 forum posts
724 photos

Patrick, welcome and feel free to chip in. I have sent you a pm to see if you can reply to that.

Last few days has seen me complete the glassing of the plane by doing the wings, again same method using peel ply as for the fuselage. I have also added a lot of little bits and pieces as I move toward putting the first coat of primer on. This includes the cockpit, where I have 3D printed a bit of a pastiche of the cockpit rather than an accurate scale cockpit, the whole plane after all is not an accurate scale model. To finish it off I have stuck on a print of the dashboard from a full scale Vulcan. I have painted the inside of the cockpit moulding matt black after putting some masks over the windows so the contents can be seen. When the plane is painted, the outside of the cockpit moulding will be painted, covering the matt black. I have glued on the 3D prints of the nose cone, tail cone and engine exhuats. I have reprinted these with thinner walls and less infill to save some weight, the exhaust nozzles have now been printed only 2 layers thick, i.e. 0.8mm. I have added the infill below the rudder, the ABS moudlings for the top rear of the jet pipes, the boards on the inboard sides of the intakes, the seperators in the inlet duct to mimic the feed into 2 turbines on the full scale, the one I have inserted have been rounded at the front and tapered at the back to minimise turbulence spilling into the fans. I have also made up the doors for the nose wheel well as I did not plank over this whilst sheeting the nose, so I did not have a section of skin to cut out for the doors. These have been duly glassed.

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Greg Minden12/04/2020 20:43:07
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50 forum posts
37 photos

doing a fine job. Did you mention what you are using for power. I am running 10s on each side and i found that i needed to put the 6s packs fully aft and the 4 s packs fwd to balance. Mine turned out a bit nose heavy. That's with the receiver and one 6 cell rcvr battery aft and one 6 cell receiver battery and the gyro fwd. I think i've got about 40 ft of wiring in mine!

PeterF12/04/2020 21:43:16
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525 forum posts
724 photos

Greg,

The fan details are a couple of posts up in answer to Martin's question, they are slightly more efficient than the Jetfan shrouds as they have a smaller motor housing, they will only take the 650 HET motors. I will power it with 4 packs of 4S 5000mAh. These are the Turnigy Heavy Duty packs and they weigh a bit more than equivalent capacity packs, in total 5lb 3oz ( 2.35kg), I already use them in an EDF pulling 105Amps without problems. The ESCs are YGE HV 120Amp units. I have some scope for moving the batteries fore and aft, all my radio gear will be at the back, but my alloy fan shrouds will be heavier than yours. Finding a plane with a forward CoG is a rarity. This is one reason I reprinted my 3D parts as the nose cone was quite heavy.

patrick mcateer13/04/2020 06:48:51
6 forum posts

good morning Peterf, I cant open the pm it keeps saying your profile is not made public. so I cant get the file.

my email address is atrickmcateer74@yahoo.co.uk">patrickmcateer74@yahoo.co.uk if you could email them to me please. im going to make a start on the wings today. the power plant im thinking of using is the lander 90mm 12 blade 10s edf units. im waiting for (tony) from robotbird to get back to me with details. do you have a picture of how you paired (wired) both batterys to give you the 10s. im going to put the battery hatch on the top of the plane as it makes sense for access.

keep up the great work

PeterF13/04/2020 11:25:32
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525 forum posts
724 photos

Patrick,

I use XT90 connectors so I added two connectors to the ESCs to give 8S from 2 4S batteries in series. The +ve pin on one connector went to the ESC +ve, the -ve pin on the other connector to the ESC -ve and then a bridging wire (shown blue in this pick) between the unused +ve and -ve pins on the connectors. This is illustrated below, but this is only a dummy pic I created with a spare ESC, the Vulcan ESCs are currently boxed in the fuselage and I can not photograph them until I cut the battery hatch free.

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patrick mcateer13/04/2020 15:19:26
6 forum posts

brill thanks Peter

Greg Minden13/04/2020 15:24:04
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50 forum posts
37 photos

Peter - the usual way to achieve multiple hookup is to use a "y" harness easily available from H King and many sources for less than $10. I will point out that my motors each draw close to 100A at full power on 10s so you might want to rethink your Turnigy 60. I am using Castle 120HV.

Greg Minden13/04/2020 15:26:20
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50 forum posts
37 photos

OOps - i see in your previous post that you are using 120A ESCs. Sorry for the confusion. But, easier hookup with the "Y" harness

PeterF19/04/2020 16:56:20
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525 forum posts
724 photos

A lot of messing about cutting out the hatches, adding linings to the edges and catches to them. I have cut the radio, battery and fan hatches, the main undercarriage doors and some air inlet slots for the ESC heat sinks. I have added air outlet slots in the radio hatch and 3D printed some air scoops for the ESC inlets and outlet ducts for the radio hatch. Like everyone else, I have put the battery access hatch on the top of the plane and made it longer than the one on the plan. During the turtle deck build, I doubled up on a couple of the formers with a small gap between them, left the location marked and cut the hatch out using a hacksaw blade.

One word of warning for anyone that follows me and makes the inlet ducts to the fans longer than on the plans, the ducts will overlap the fan hatches and if like me you waited until the end to cut these hatches, then the ducts and the hatches were glued together. If you do this, then when fitting the fan inlet ducts DO NOT put glue on the bottom of the ducts in front of the fans.

I have also very lightly sanded everything in preparation for a coat of high build primer to knock back the stippled texture from the peel ply without going into the glass cloth.

I am amazed how much time I have spent on these tasks and the build does not appear a lot further forward, I suppose because there is no real visible additions to the aircraft.

Fan hatch and ESC air inlet slot cut out. Notice overlap of fan inlet duct and hatch.dsc08928.jpg

Fan hatch fitteddsc08948.jpg

ESC air inlet slot and start of ESC heat sinkdsc08931.jpg

3D printed air scoops for ESC cooling air inletdsc08942.jpg

Radio access hatch with 3D printed air outlet ducts. This is in the plan position.dsc08944.jpg

Battery access hatch completed in open positiondsc08957.jpg

Looking forward in battery compartment to the ESCsdsc08938.jpg

Battery hatch closeddsc08959.jpg

Edited By PeterF on 19/04/2020 16:58:22

PeterF26/04/2020 17:32:55
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525 forum posts
724 photos

One week since the last update, and this has consisted of 2 days applying a thick coat of high build primer (2 pack acrylic) and 5 days of sanding it down. I am now at the stage where I have to do some areas with a second coat of the high build primer to fill a few imperfections before I can apply a final light coat of primer. I was worried that the solvents in the primer would attack the PLA 3D printed parts, but that has not been the case after a test piece so this has filled the prints and has left them perfectly smooth. Since I am going nowhere it is keeping me occupied.

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patrick mcateer27/04/2020 07:34:26
6 forum posts

Nice work Peterf, im waiting for my edfs to come they are the 12bl 10s, i havent done much more as im waiting for them to come. im still not sure of the esc to get for them but ill keep looking. im also going to be putting the hatch on the top. i will take some photos and put them up. also peter i bought a 3d printer and bulit it so that i can print your parts out that you sent me. just having some teething problems with printer lol but ill sort it,

keep up the good work oh were did you get your primer from

PeterF27/04/2020 10:01:04
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525 forum posts
724 photos

Patrick,

I used high build primer from Jawall, see here with the appropriate thinners, see here.

I found a lot of useful info on a thread about peel ply application earlier in the year, see here including primers and the fact that some people had brushed high build primers.I do not have spray equipment so I brushed it on, I needed to add more thinners to get a good brushable mixture without it going thick too quickly when brushed out.

The high build primer I use is an isocyanate based paint, hence has a lot of health warnings if it is being sprayed as the isocyanate is a sensitiser if inhaled or in contact with skin. As I was brushing I was less worried but still applied it wearing disposable gloves in a well ventilated area.

I will email you the air vent files in case you are also interested in these.

2k high build primer kit 1.5litre.jpg

2k basecoat thinner 1litre.jpg

Edited By PeterF on 27/04/2020 10:01:53

patrick mcateer27/04/2020 10:15:26
6 forum posts

Good morning Peter, yes please i will have those files. i have never covered a plane in glass clothing so i will be reading up alot and doing sample tests when i get that far.

i have had alot of triuble trying to find the 12b 10s edf but managed to get them, they are the lander units but im not sure about esc to get for them as im new to electric i usually fly petrol and nitro. your build and greggs build has being helping me alot.

thanks

Patrick

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