1st Scratch build recommendations.

[Hogster]

I expect this question has been asked lots of times but after searching the forum I`m still not quite sure. Let me explain where I`m coming from.

 

My building and flying experience is low. I have built one plane from a kit and one ARTF. Now, I run a model club at school and I want to get the kids to build a fully functional R/c plane from scratch. The idea being that they use the CAD/CAM knowledge they learn during lesson time to build from a plan as if going into production.  But we will only build a 1 off.  Along the way we will look into the theory of flight and the various properties of the material  used in the build and so on. My intention is to get it flight ready and for us to take it to my club field and maiden it. Am I being over ambitious?

 

I have an engineering background and I do have one or two experienced builder friends who will help but I would like some recommendations for an easy build and fly scratch build project. The age group will be mostly 11-14 and I`m thinking something suitable for a .30-40 2stroke and 4 channel.

 

This sort of project has so many cross curricula issues from  Design & Technology to Physics, Chemistry, Geography that the idea has been well recieved by many staff. I`m keen to get started and so input from the forum is very welcome.

[Ian Skeldon 1]

In order to meet the requirements you have stated and to maximise your chance of success, I would recomend something like the Ben Buckle Super 60, but go for the aileron wing version.

This will allow you to build cheaply and will only need the ribs and bulkheads to be cut using the cad/cam facility. In fact you could take the original drawing and increase it to 150% if you wanted a big, slow flying model that pupils could use to learn to fly with.

 

You could even do away with the traditional stick and tissue fus build and make lightened and strengthened sheet sides if you really wanted to. The model could be lipo/life powered or IC powered dependant on your choice.

 

Final tip would be to use rudder as the primary roll/yaw function and mix aileron with it in a CAR mix type situation.

 

You might also want to get the pupils to design and build a battery charger, battery voltage indicator, on board glo etc, etc.

 

I wish you every success with this and hope the pupils gain knowledge and interest in model flyiong from doing this.

 

Ian

[kc]

Surely this enquiry illustrates why there are so few practical younger people now!  All the practical people of older generations were shown plans and told to make the item exactly to the plan.   Then after years of practice they might have learnt enough to make their own design.

 

Now people think they know enough, without ever having  made anything, to  draw up the plan!   Its like teaching running before they can walk.

You dont need to know anything about CAD/CAM to build a beginners plane.  Start by teaching them to build exactly to a proven plan. Learn craftsmanship first.  Let them all build a Super 60 or the smaller / cheaper Mini Super from the David Boddington / AMI plan.

[Hogster]

Ian: Thanks for your suggestion. Thats very helpful.

 

kc: You`re right, you dont need to know anything about CAD/CAM to build from plans, but as one of the curriculum topics is CAD/CAM and the students are expected to produce a piece of work using these principles I thought it might be a bit more interesting than a CD rack or pencil case.....I suspect we will end up doing a mixture of both methods anyway.

[Steve W-O]

I think it is a great idea, however given the time constraints and dealing with a whole class, I think building a full kit might be slightly ambitious.

 

Risking being shot down for not being qualified to design something I would suggest this as a possible idea.

 

Use 6mm depron as a basic material, flat wing and simple box fuselage.

 

Decide on a wingspan of about 40", then the rest something like main wing aspect raitio 5 or 6:1, fuselage length about 4/5 wingspan, area of tailplane about 1/4 of main wing, tail fin about 1/3 of the tailplane, elevator about 1/5 of tail plane, and rudder about 1/4 of the fin. Dihedral 5deg, power round 50W/lb, CoG 1/3 back from the from of the wing.

 

You can use ramin strips from the hardware tor for the main spar and fuselage frame, probably cost £3 for all you need, one sheet of depron will be enough with spare, two cheap 9g servos and a 20A ESC, and a £5 motor, prop and adaptor. Couple of wheels, some hinges, control horns and snakes, small amount of 1/8" ply and it will be flying.

 

I would almost guarantee it will fly well, can easily be drawn as a CAD project, the foam can be cut on a simple CNC cutter if your school has one, and it is simple enough to achieve in the class.

 

It won't look as good as an ARTF, but it will be fully built without all the time consuming and difficult to co-ordinate aspects of a fully built up model with many people taking part.

[kc]

I would suggest that the curriculum is wrong if it gives more emphasis to learning CAD/CAM instead of learning to make things with ones hands!

For each CAD/CAM skilled person this country needs hundreds of carpenters, plumbers, mechanics etc.  CAD/CAM wont help anyone fit a door to their house or mend their shed etc.  A country full of people who cannot use their hands can only throw away things that have the slightest fault.

Aeromodelling the traditional way with craft knife, saw and sanding block can teach the basics of craft skills whilst producing a satisying object that can be used, all at low cost.

Teach real aeromodelling!

[Andy Gates]

How about an easier first step?

 

Have a look around at the RTP thread (round the pole).

 

The students can make up the power supply using items already likely to be in the schools physics lab,

the pole could be made in design & tech lesson,

the planes can be a couple of the easy to build models available,

and better still all models can be flown in the school hall / gym / backetball courts regardless of weather.

 

The progression could be made into desining their own models, either profile of fully built up which would fulfill the CAD/CAM criteria.

Different wings can be made for some machines to look at the difference in wing profile / flaps.

Localised heat sources can show thermal activity when pushed into place after take off.

 

On the fun side, streamer cutting combat can be undertaken, races or flying accuracy targets set.

You could also try a heaviest take off load with a view to progressing to the Student Radio Controlled Heavy Lift competition.

 

Best of all the cost to the school is likely to be negligable, and if the students are interested this could branch into an after school activity.

[Steve W-O]

Posted by kc on 05/10/2010 17:18:49:

I would suggest that the curriculum is wrong if it gives more emphasis to learning CAD/CAM instead of learning to make things with ones hands!

For each CAD/CAM skilled person this country needs hundreds of carpenters, plumbers, mechanics etc.  CAD/CAM wont help anyone fit a door to their house or mend their shed etc.  A country full of people who cannot use their hands can only throw away things that have the slightest fault.

Aeromodelling the traditional way with craft knife, saw and sanding block can teach the basics of craft skills whilst producing a satisying object that can be used, all at low cost.

Teach real aeromodelling!

 

 

I'm sure many would agree the curriculum is wrong, but it is there, and it has to be adhered to (by government funded schools)

 

The point is that aeromodelling is not part of the curriculum, the OP is trying to find ways to involve something interesting within the confines of the curriculum.

 

 For that, I think he deserves positive ideas that will help in his aims!!!

[Braddock, VC]

My club is doing a similar scheme with a local independant prep school, in return for flying facilities.

The way we started is with bmfa aerojets, then Darts then Jiminy Crickets. This gives us a good idea of the relative abilities of the children when it comes to the next project which will almost certainly be either a junior 60 or a super 60. This has to be ready for the next flying season.

The children are mentored by club members and the legal aspect is covered by the fact that their teachers are present.

We will split the children into teams and each will construct part of the model along the lines of airbus industries and learn communication and negotiating skills along the way.  the project manager of each team will be the student who has demonstrated the greatest ability, with the best being given the more difficult structures.

It's made more interesting given their are three european nationalities involved so it's almost more airbus than airbus.

The biggest problem is we only get them for about an hour a week and a fair proportion of that time is given over to them flying their creations.

It's certainly a great stress relief to watch these young people working away, though they are younger than the OPs group being 7 to 11.

[Hogster]

Posted by Steve W-O on 05/10/2010 17:42:06:

Posted by kc on 05/10/2010 17:18:49:

I would suggest that the curriculum is wrong if it gives more emphasis to learning CAD/CAM instead of learning to make things with ones hands!

For each CAD/CAM skilled person this country needs hundreds of carpenters, plumbers, mechanics etc.  CAD/CAM wont help anyone fit a door to their house or mend their shed etc.  A country full of people who cannot use their hands can only throw away things that have the slightest fault.

Aeromodelling the traditional way with craft knife, saw and sanding block can teach the basics of craft skills whilst producing a satisying object that can be used, all at low cost.

Teach real aeromodelling!

 

 

I'm sure many would agree the curriculum is wrong, but it is there, and it has to be adhered to (by government funded schools)

 

The point is that aeromodelling is not part of the curriculum, the OP is trying to find ways to involve something interesting within the confines of the curriculum.

 

 For that, I think he deserves positive ideas that will help in his aims!!!

 

 I dont want this to turn into a discussion on the national curriculum but, CAD/CAM is on the curriculum as well as the more traditional wood and metalworking, not instead of. And what is taught in the curriculum is based on what employers want. That is highly skilled and educated school leavers. They would rather employ someone who can design a shed than someone who can mend it
However this project is an after school project and as such will be attended by students who have modelling as a particular interest.

John Gibbs club project seems to be along the same lines as I envisage. I have already checked out the BMFA education packs and intend to place an order for the dart.

 

[Myron Beaumont]

kc

 Havn't had time to read the contents & replies to this thread yet,but as soon as you mentioned CAD etc ,I thought -Oh NO ! Computers seem to "rule OK".

Get a load of Balsa wood & get them to learn how to use a plan (or make their own )

They'll never really learn the starting fundementals otherwise

As for the flying bit ,you'd better just get them a simulator or another fresh off the production line import from China

Call me old fashioned -but I know what's wrong with so-called new educational techniques -It worked for me & others with grey hair (or none) in the original format .40's & 50's

Having said all that ,I wish you the best of luck .At least you're having a go

Myron

Edited By Myron Beaumont on 05/10/2010 21:31:17

[Braddock, VC]

Personally I think hogsters got the right idea. All the criticism about starting from other reference points completely ignores the fact that kids have gone their own way for a long time. Just like the artf revolution this is coming to an end and if hogster can use the tools that turned the kids to turn them back to the skills zone then I'm up for it and, as a boring old fart, can say to the others who have raised alternatives, get real.

[Simon Chaddock]

Hogster

As you might detect from my posts on this site I would support a depron/electric approach.

 

Depron is cheap, easy to cut and glues well but to demonstrate "design" create proper built up structures with it as well..

Thin Depron sheet is so light almost any framework can also be completely skinned with it as well.

 

From the sort of basic design dimensions as suggested by Steve W-O, use CAD to accurately draw out each component part. Its what CAD is good at and it is so tedious to accurately do by hand.

 

Kept to modest dimensions and with lightweight RC gear, the design may be one off but it could easily be replicated. An important attribute considering the high risks of own design and flight trials!

 

I am sure we will all be most interested to know how you get on.

[Hogster]

Thanks for all your suggestions. I`ve noted them for future  reference as I`m still in the planning stage and the club has just started. But interest from the students is encouraging. I`ll keep you posted on how we get on.

[Ernie]

Hi Hogster,

please be careful. Like you I tried a similar project with a gang of air cadets around 14 years old

First, do it......but beware of a bundle of problems.

The youngsters don't always have the building skills that you might expect. I had to spend hours undoing all the building faults

One lad (his dad was a plumber) offered to build a tinplate tank. Great, but it weighed more than the entire plane

Also attention spans are low, unless things can be seen to happen fast

Take them flying from time to time. That goes down well. I got a super 60 up very high, and handed over to a wee lassie. Why are you not keeping it level I asked.

Cant see it without my glasses she said.

 

go for it

ernie