Model Boat Mayhem

Mess Deck: General Section => Other Hobbies and Interests => Topic started by: Andy M on October 28, 2019, 05:20:34 pm

Title: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on October 28, 2019, 05:20:34 pm
Hi, I am looking for sea knight helicopter cross sections if anyone knows where I could find them? I have searched but only came up with some grainy 3 views so far. Any help would be appreciated, thanks
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: KitS on October 28, 2019, 10:25:03 pm
Fujumi do a 1/72 scale plastic kit of the Sea Knight. You could get one of them and measure the profiles of it maybe?
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on October 28, 2019, 11:32:38 pm
Hi, I had thought about that, but was trying to keep my project costs as low as possible, I had hoped there would be more detailed drawings available online, or maybe a model plan. There are plenty of plans for model planes but very little in the way of helicopters, I may just have to accept it and work from the drawings I have. When I scaled them up (on my ageing laptop) for tracing at the size I want, the lines end up 5 mm thick! Do I use outer edge,inner edge or the middle? And are the drawings that good anyway? I have started drawing it anyway, I sometimes get too caught up in details, but I would like my model to be fairly close,  small proportion differences can affect the whole look. I have airhogs twin trooper which has pretty accurate shape, apart from the rear rotor gear housing area. I must admit that it doesnt stand out too much tho. And it flies, so any scale inaccuracies are ok. It is a challenge to fly it tho, no gyro on this one. A lot of fun tho, and looks good in the air, the reason I am building a more controllable version, at a bigger scale. I will stick some photos on here once I have progress to report.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: TailUK on October 29, 2019, 08:36:13 am
As far as I can see the fuselage cross section is consistent down the whole length.  A front view should give you a cross section.  What scale are you working in?
 
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: TailUK on October 29, 2019, 08:45:32 am
Hold the presses. Just found the drawing!  PM if you want a bigger version.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: KitS on October 29, 2019, 08:52:29 am
Note that that drawing is of the Swedish Air Force version which has additional sponsons on the stub wings for additional stability when landing on water.  IIRC that's the only military version of the H-46 that has these fitted.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: TailUK on October 29, 2019, 08:58:49 am
OK, but close is better than nothing!  Andy did seem to be worried, mostly, about cross sections.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: KitS on October 29, 2019, 10:23:11 am

Absolutely, and it's a pretty good drawing too.  :-))


I've been 'aboard' the H-46 they have in the Swedish Air Force Museum at Linkoping, and it's like a mini-Chinook inside. Which isn't really surprising I guess as that's pretty much what it is!  :-) ok2
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: warspite on October 29, 2019, 11:59:46 am
or these from the airfix version
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on October 29, 2019, 04:50:58 pm
Hi, thanks for putting the drawings on here, much appreciated. I am going to build my model at 28 inches long, which gives a scale of 1/19.2 an unusual scale but sized to fit both my materials and the mechanics I am going to use. I have fairly strict weight constraints too, so construction has to be mainly balsa with small local reinforcing bits of ply and carbon. I will post photos as it progresses.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on November 04, 2019, 04:33:14 pm
Having scaled up all the various drawings I have, I have discovered they are all different. Some by small amounts, some by a considerable amount. As a result, I have decided that my model will have to be semi scale, which is ok as it is intended to be for flying rather than an accurate scale model. It would have been nice to have started with accurate drawings, but I will continue with what I have. I am looking forward to starting my build and would like to thank those that supplied drawings. I will put photos on here once I start cutting and glueing balsa.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on November 12, 2019, 05:57:55 pm
After a bit of planning, cutting and glueing, I have my main fuselage 'tube' made up. Still a long way to go but having the main frame started is a bit of a boost. Once the frame is fully glued and fuselage stringers added, I will be carefully sanding the outer surface ready for the skins to go on. I will post more photos as it progresses.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on November 13, 2019, 09:03:35 am
A bit more progress.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on November 14, 2019, 04:46:48 am
A bit more work and its starting to look good (to me anyway)
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: TailUK on November 14, 2019, 08:21:14 am
Nice!  Really coming together.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on November 14, 2019, 06:14:10 pm
Thanks, the sponsons are just pinned in place at the moment, I am planning on final fixing once the fuselage is skinned. Lots and lots still to do but getting the main bits done quite quick. Still suffering from not having plans as good as I had hoped. I knew I the plans werent that good as soon as I spotted the drive shaft tunnel (on the 'roof' of the fuselage) is shown in the centre, this is completely wrong and quite a major mistake for a drawing. Measuring other drawings gave me an average position/dimensions to work to.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on November 16, 2019, 06:17:27 pm
A lot of glueing and pinning later and I have a mostly skinned fuselage. Lots still to do, rotor and engine housings, rear fuselage and cargo ramp/door. I will do some sort of cockpit detailing but I have to think of the weight. I have still to work out construction for the remaining items, based on my collection of different drawings.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on November 18, 2019, 08:07:32 pm
A bit more done last night. The black and white photo shows boeing engineers with a model roughly the same size as mine will be.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: RST on November 18, 2019, 08:56:13 pm
Nice and may I ask how you cut the circular windows?  I've tried compass cutters (2 types), holesaws, reamers, everything seems to leave a ragged edge. Best I've done is wet'n dry wrapped round a reamer.  Yours look nice and crisp in comparison!


Rich
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on November 18, 2019, 09:32:03 pm
Hi, I cut them out roughly with spiralux saw then 13 mm drum sander in dremel type drill out to my line. I still have to sand the edges, that is how they looked after the drum sander. (And a steady hand) it is 1/32 balsa so it disappears quick so youhave to be careful, very careful.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on November 26, 2019, 05:16:33 pm
I have purchased a 1/72 diecast model of a seaknight for measuring and scaling up to produce drawings for building my model, while this has been really useful, it does have its own inaccuracies, most obvious of which is paint related,which isnt a major problem, but affects the overall look of the aircraft. I have included photos which show this. The seaknight is known for its mouth shaped lower glazing, this has been painted wrongly on the diecast model, kind of spoiling the model.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on December 06, 2019, 05:01:03 pm
More progress, I was wanting to build the whole aircraft from balsa but due to the complex shapes of the rotor masts, I decided to use foam. I have made the rear section with rotor mast detachable, held with small magnets and 2 wire pegs. Still lot of sanding and shaping to do, sponson ends will be foam too. Nose section also to be finished.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on December 06, 2019, 05:08:28 pm
I made a start on my wheels, I used 2 layers of 1/8 liteply and spun them in my drill while holding a sanding block against them.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on December 06, 2019, 05:17:23 pm
Here is a small project I had an idea for, an 18v cordless strimmer, given to me because the battery was dead, a 14v drill, same dead battery problem. I decided to mount them to a base with sandpaper attached to them. Strimmer motor had a plate that looked perfect for a 1/8 ply disc to be glued onto and sandpaper attached with double sided tape. The drill motor has a gear on it, I found plastic tube that pushed over the gear and tightly fitted a sanding drum. I am happy to say my mini sanding centre works perfectly and cost zero. Recycling is fun.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: RST on December 06, 2019, 09:04:11 pm
1. Nowt wrong with carving foam -presumably everything is skinned everyway. I just got some scrap XPS foamboard myself to start trying!
2. You've given me some ideas for rehabilitating old "U/S" tools now I can 3-D print up to 300x300x400mm!
3. You should re-title this thread as it's an interesting build rather than a request for drawings now. Ask admin to do it -its always nice to see other builds and flying folk always impress me with lightness of construction


Rich
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on December 06, 2019, 10:57:19 pm
Hi, I dont know how to go about doing that. I did wonder if I could edit the title. As to the lightness, using 1/32 balsa sheet helped, but I should have checked the weight of the scrap 1/16 and 1/8 balsa formers, and how many I was putting in. It waa a delicate structure to work on, sanding it caused a few breakages. Once the outer skins were on, it became less delicate. It is approaching my weight limit already, things always end up heavier than you think. The rear foam section after rough shaping, was over 40 grams. After sanding the outside, this only dropped to 36 g. In an effort to shed weight, I have removed foam and balsa from the inside with 13mm drum sander, this has now dropped the weight to just under 30. I want the airframe to be able to take flying and landing stresses, so I cant lighten things too much. I still have some sanding to do on the nose, then sanding drum to hollow it as much as possible. I still think I have to lose a bit of weight for decent flight performance.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Martin (Admin) on December 08, 2019, 10:57:14 pm
Topic renamed....
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on December 08, 2019, 11:13:12 pm
Many thanks to Martin for renaming my topic. I will post more pics as things progress. I have cut out the cockpit door windows, cut plastic sheet to fit front window, attached foam sponson tips, filled various areas and remade my undercarriage. I had made a set using 2 layers of liteply and a layer of 1/16 balsa each side for each wheel, I used an old tx aerial for main bit of strut, inside a plastic tube and a lighter spring inside. Kebab stick was used for axles. Total weight 20g.I decided to make a lighter set using just balsa for the wheels and dowel for main strut. I am happy to report a significant weight saving over my original ones. New weight is 6g! A saving of 14g, just for choosing different materials. The whole project has taken on a weight reduction element.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on December 09, 2019, 12:00:51 am
The tail unit has had 16g of material removed. Not the prettiest, but effective. The forward rotor mast housing has had 3g removed, leaving it at 7g. The wheels and sprung struts on the left are 20g, the wheels and solid wood struts on the right weigh in at 6g. Another useful weight saving.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: tigertiger on December 09, 2019, 05:14:43 am
I did wonder if I could edit the title.
   






We can do that for you.
It will change the title of the thread, and every future post.


What do you want the new title to be?
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on December 09, 2019, 09:07:14 am
Hi, Martin has already changed it for me. Thanks anyway.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on December 12, 2019, 03:01:58 pm
A bit more progress over the weekend has it ready for painting. I also did more weight trimming, tiny amounts but it all adds up?
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on December 12, 2019, 03:45:07 pm
I painted the cockpit interior black, I did want to build an interior of some sort, but extra weight isnt welcome at this stage. Anyway two coats of paint later..... And also my new, light weight undercarriage, compared to a tea biscuit.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on December 12, 2019, 08:22:15 pm
Looking good with some paint. Still on a mission to shed more weight tho.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on December 12, 2019, 08:38:25 pm
A small disaster, just to spice up my project, heavy rain and strong winds blew water up under my shed roof ridge and right into my model. Water poured out when I lifted it up. Large areas of my sheeting had swollen and come away from the frames and gone a wavey shape. The areas that lifted are indicated by each pin. Bit of a panic but I seem to have saved it pretty well.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on January 01, 2020, 08:45:31 pm
Hi, some more photos of progress. I decided to build a bit of detail into the cockpit, only thing was that between the cockpit and windows, this added 20g to my airframe. Doesnt sound much but it put the weight over my max. So I did some lightening on the bits I could. I show a block of foam which weighs a gram. Also 3 g of balsa I removed. I took a lot of weight off the rear rotor pylon, mostly foam, some balsa. I got back my 20g and a bit more off the main airframe. I made a guage to tell how thin I was going with the foam. 1.5mm is my thinnest bit.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on January 01, 2020, 08:47:31 pm
Instrument panel and a side view.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on January 01, 2020, 08:58:58 pm
A photo of the insides of my hollowed out parts. My guage for thickness measurement and a mini longnose sander I made from meccano
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on January 02, 2020, 11:07:11 pm
I had hopes of adding lots of detail on this model, I was hoping to have the loading ramp operated by a spare channel but weight restrictions mean I cant manage that anymore. I had also hoped to finish the cockpit with some seats and a carved foam pilot. My weight problem has resulted in extensive efforts to lose every spare gram. I managed to lose enough weight to get back within my target weight. Even as far as cutting out the sliding windows on the pilots doors,  saving a grand total of 0.25g. I also trimmed every fuselage rib, which was a challenge to do without breaking anything.  I used a scalpel blade, bound to a dowel with thread and superglued.. this gave me the reach to get in and carve away at the inside of my fuselage. I took about 3mm off each one.  I managed to halve the weight of the rear doors and decent weight reductions on other bits. Having lightened the sponsons during construction, I decided to try and get more weight out of this area, using my extended scalpel through the windows and my homemade long nose sander to try and tidy up the holes a  bit, I managed to get another gram or so out of my airframe.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on January 03, 2020, 01:16:13 pm
It flies! And with no shortage of power, my weight saving worked.  Video here   https://youtu.be/qtf1zaQAeaA

Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on January 03, 2020, 03:45:37 pm
I had also planned to build scale rotors and gear them together but this would have been well outside my weight limit. I still fancy doing a set for display purposes. My pylons wouldnt take flying loads produced by freewheeling rotors anyway. I have enjoyed this project, it has posed a few problems that I eventually solved, but some that it was too late to rectify. The floor has a full length 1/4 balsa spine up the middle and a 1/8 spine either side. These could have been reduced in size, also the formers/bulkheads/ribs? could have been selected for lightness rather than a random selection from my scraps box. It is pretty strong though, I was  doing a tight turn at low height and caught a wheel, rolling it over, with no damage. I must say it performs better than I expected, it is loading the quadcopter quite a bit but it copes with no problems. Total outlay for this project was 10 sheets of 1/32 x 4 x 18 inch balsa (£14 delivered) a selection from my scraps box (maybe £6 worth) and a wltoys v262 quadcopter (£15 delivered, amazing value) These are good as standard (the ultimate collie excersising device)but are capable of carrying a decent load, especially once the epp bodyshell (85g) is taken off.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on January 05, 2020, 02:47:54 pm
If anyone fancies a wltoys v262, I would advise that the motors be run in before flying, this involves oiling the bushes and removing the props, I also removed the motor covers as these prevent cooling. The motors are run at first speed for about 10 seconds then allowed to cool, then 20 seconds and 30 seconds. After short time cooling I was giving it a bit more throttle in short bursts then building up to constant full throttle bursts of 10 seconds or so. The change in the motor noise as they bed in is noticeable. It only takes a total of 10 to 15 minutes to run them in and it will make the motors last longer. I found a website with lots on info about them and one thing that was repeated was importance of running the motors in.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on January 11, 2020, 10:39:07 pm
This project is essentially finished, I have to add markings of course, but dont think I can paint fine enought to do them justice, painting the foam neatly being hard as it isnt too smooth, and I cant afford the weight of filling it and repainting now. Tranfers, if they exist at 1/19 scale, would be ok on balsa bits but grainy foam, probably not. Anyway, after I discovered that weight was real tight, I decided to stop adding stuff to it,  I had planned to do seats, pilot, spare channel rear door opening, scale rotors geared together and even had hopes of lifting a cargo package slung underneath. Ah well. It was made to fly, so I am going to enjoy that as number one concern rather than scale colour scheme. I am still unsure about drawing on panel lines with a fine pen or not. It looks good enough for me without them from a flying point of view but I would still like to see them on there. I am worred it looks too obvious from a distance. I have a 0.3 mm pen, at 1/19 scale is just under 6mm wide seams on the full size. Mmm. Maybe not then. Could glue black hairs on I suppose, lol. Wheres the dog? Lol. The most obvious scale improvement would be a foam pilot and seat as you can see in the windows easily. I need to see how light a pilot/seat unit I can come up with.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on January 19, 2020, 09:55:36 pm
Here is some onboard footage from my seaknight     https://youtu.be/ze7rfI3eL5A
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on January 19, 2020, 10:01:34 pm
I feel a lot more comfortable flying this than a proper helicopter. It seems to cope better with heavy landings than any helicopter I have ever had. I am glad it has enough power in reserve to carry my mini camera, all my lightening efforts are rewarded.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: tigertiger on January 25, 2020, 02:03:23 am
***Topic split***
New topic here [size=78%]https://www.modelboatmayhem.co.uk/forum/index.php/topic,64360.0.html (https://www.modelboatmayhem.co.uk/forum/index.php/topic,64360.0.html)[/size]
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on February 07, 2020, 08:55:36 pm
Here is the little airhogs twin trooper that inspired me to build my seaknight, it is a challenge to fly!  https://youtu.be/LSMsyrnDdpQ
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on February 08, 2020, 02:09:25 pm
I had a couple of flights with the seaknight yesterday while a second coat of yellow was drying on my jetranger. The seaknight doesn't display the same tail dip that the jetranger does. It flies well, I seem to have removed enough weight for it to cope well with what's left. Next thing to do on it is markings, even just a few to add to the look.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on February 12, 2020, 11:38:54 pm
I was given a set of ditigal scales capable of weighing my helicopters I could only weigh to 100g accurately before. Now I can say that ready to fly with standard 7.4v 850 mah battery it weighs in at 415g. 50g heavier than jet ranger. It still flies really well so it's promising for my jet ranger knowing it can handle at least 50g of cockpit detailing and maybe enough left over fo carrying my fake main rotor aloft too? I certainly hope so, I was disappointed that I didn't have enough weight carrying ability left on the seaknight to include a dummy rotor system. The two rotors would have required linking with a geared shaft so they don't hit each other. I am sure I could build another seaknight a bit lighter now I have learned from it and the jet ranger.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: warspite on February 13, 2020, 08:59:20 am
you could do an iconic Chinook or stalion
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on February 13, 2020, 10:05:37 am
I was looking at the chinook but wasn't sure if my quad motors would cope with the extra size, if I did it at same scale as the seaknight. I think it would if I can keep the weight down. The jet ranger ended up pretty light, the tail boom is quite spindly but the undercarriage is 30g. All my seaknight landing gear is 6g, 1/5th of the weight. If I make chinook landing gear same way, they should be around 8g. 22g is about 3 sheets of 1/32 x 4 x 18 inch balsa. I overbuilt the seaknight, but it means it is pretty durable. I have had it roll completely over with no damage. I have a list of helis that I want to build for quad motors.
Cobra
Skycrane
Chinook
I also have my hornet wasp to build, as soon as I am happy with my plans.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on February 13, 2020, 06:07:25 pm
Having just received 12 sheets of 1/32 x 4 x 36 inch balsa through the post, it is tempting me towards building the skycrane. I would be building it to the same scale as the seaknight, I would have built the jet ranger at that scale as well, but I had the rotors as close together as they could go. To be honest, making the jet ranger at 4 feet long instead of my ones 3 feet would have resulted in better handling characteristics, I think I could have built it at about same weight as the seaknight. Anyway, the skycrane works out around the 45 inch mark. But I am relying on its spindly structure to keep the weight down for such a big heli.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on February 13, 2020, 06:18:53 pm
Several years ago..I built a skycrane bodyshell for a walkera 5#8 Co axial helicopter. Again, weight was critical. Also the rotor wash was blowing down on the tail boom causing a pendulum effect.
This video shows that it did manage to fly though.
https://youtu.be/ro5GQToqkdc
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on February 19, 2020, 10:25:49 pm
Having not commented on my seaknight for some time, I thought I should report on it. It flies exceptionally well, exactly as I had hoped and maybe even a bit better as I got a bit carried away with my lightening measures. It flies better than the jetranger. The only thing I think I really have to do is work out a better way of hingeing the rear ramp / top hatch as they are just held on with grey painted masking tape at the moment, and I mean just held on. I could just glue them in, but I want them to open as I still have a spare channel if I can build a light enough operating mechanism. Not critical that I have that but would be nice feature. Even if it turns out the ramp just hangs with threads supporting it that would do me.
Title: Re: Boeing Vertol CH-46 Sea Knight - My helicopter build
Post by: Andy M on April 25, 2020, 10:30:47 pm
I have decided to tidy up the ramp area by removing all my grey painted masking tape hinges and holding closed bits, I was going to try and hinge it all properly, but weight prevents that so I have tack glued it all together so I can fly it without bits dropping off