eclipsegsxr

I got ahold of some plans for a trainer ..Yes I know why sratch a trainer and not get an ARF???... Well I planed on making 2 wings for this plane one with the trainer wing and one for sport when I get better.. My question is it doesn't have Ailerons on the wing..it has only Rudder and elevator.. I have learned that Ailerons work alot better than with out them.. I do plan to alos try and set this up with one servo to contol the ailerons. Is there anyone out there that could make the changes for me ar tell me how to do it and also design a sport wing for the plane also.. This is my fisrt plane I'm doing and just getting into the Hobby.. I figured I'd scratch my first plane...More fun that way and give me something to do....

Brad

Team MPP

Can you tell us what the plan is called. Also, do you have CAD or something to be able to transfer drawings of a second sports wing?

eclipsegsxr

yes I have a cad file of the plane..The file for the plane is called PROTRAIN..The main thing I'm looking for now is to get ailerons on the trainer wing..It don't have them..I'd think it would bet better if it did...I'm going to upload the plan of what I got to my website..You'll find it under the Free plans area..

[link=http://members.lycos.co.uk/eclipsegsxr/FMS/]My site[/link]

Team MPP

I can update the design to incorporate ailerons. What would you rather have. Strips along the majority of the surface or just shorter barndoor type ailerons. The dihedral angle will have to be lowered considerably. Those wing braces look very steep.

As for the sports wing. Do you want it symetrical in shape or with a slightly flatter bottom edge?

eclipsegsxr

The sport wings that i would like, it an airfiol that is good for loops and maybe some inverted flights.. As for the ailerons I'd like the size to be somewhat close to that of the Tail elevators..Not to big but not too small either..yes this beast has huge Dihedral in it one wing side flat one surface then 10" to the bottom of the wing in the Air..I was considering cutting it Down to around 5" Dihedral that should be enough to keep it stable and be good to learn on...As I have never flown Yet.

Team MPP

I would recommend making the dyhedral around 2in (1in per side). This will still be very stable for a trainer especially with ailerons. If you are just learning to fly I would also recommend strip ailerons along the whole wing. They tend to be more docile and forgiving.

Leave the bigger ailerons for the sporty symetrical wing for once you have learned the basic art of flying.

eclipsegsxr

OK ..sounds good I'll go with that...Can you make the changes for me?
I appreciate you help in this very much...

when you have the plans altered you can e-mail then to me at [email protected].
Also MY idea for the ailerons was to use the area that they skined in the plans an turn that into the aileron at the trailing edge. I think that would work out OK..what do you think..

thanks again,
brad

BMatthews

I hate to say this but there are so many glaring design flaws in the PROTRAIN plan that I would regretfully but strongly suggest that you choose another design.

The airfoil is much too thick and oddly shaped, the dihedral is a ridiculously high angle and the rudder is too small. This design would fly as though it was fighting upstream through mollasses, the steep dihedral angle will make it super sensitive to crosswinds during takeoffs and landings and I'm sure the angle is high enough that in air turbulence will have it dancing around like a wobbly gliding pigeon. The only good thing is that the small rudder combined with the crazy dihedral angle SHOULD make for decent response. But if the airfoil drag ever let's it speed up the rudder control will become overly sensitive and tend to flick the model around.

I rarely offer such condemnation for any design but this one would need a complete redo IMHO. There are much better alternatives for you out there. If this design has been built before I'd be very interested in hearing about the designer's theories. It may be that all these "flaws" come together to offset each other and the overall model is as gentle as a kitten but at first glance this thing seems all wrong. Sorry to blast the PROTRAIN design like that but I thing you would be wise to look for something else from what I see so far.

While ailerons are nice you can obtain very good control authourity from a properley designed rudder and elevator model. Also having one less stick to worry about makes the learning task much easier. But you are on the right track with using the 3 channels for now and make a second wing for later. If you have access to a club that will train you then you don't really need to do any of this. Make it a 4 channel model and they will set it up for gentle control response and train you to deal with it. For the second wing you will probably want to use a more symetrical airfoil for easier inverted flight. The wing saddle area on the fuselage will probably have to be modified when that goes on or the wing can be set up to fit by using a special center section. Strips or barndoors, in my experience it doesn't reallly matter in terms of flying. The degree of control authourity in either comes from the width and amount of throw rather than anything inherent in the design. Strips are considered to be easier to make as the trailing edge is just a blunt shape with simple TE stock hinged on afterwards. The servo, pushrod and control horns are easier to do with strips as well. Overall much less work.

Team MPP

Eclipsegsxr - I would really listen to what Bruce says on this matter. He is one of the most experienced persons on this forum (if not the most experienced) and really knows his stuff. If you want I have a trainer design of my own that flies really nice.

Just tell me what engine size you would prefer and I can get the plans drew up completely for that engine.

I dont really know the Protrain plane at all so I wasnt able to comment on its characteristics. Let me know if you want to use my design.

eclipsegsxr

OK ..I'll take you up on the Trainer plan offer...I'll probably run the Evolution motor that comes on the Alpha Trainer..My local hobby shop has the engines and the Complete line of parts for it and the Guy swears by it..He runs them and thinks they are the easiest for beginners..I'll probably run an engine in the .40-.46 range..

Just to Clear alittle more Air on this..I didn't design this plane..I'm simply making some major changes to Make this a better plane..

Hope this is helpfull..
If you see anything I've overlooked..Please let me know..

Brad


Team MPP
would you still be able to set it up so i can have the option of changeing the wings like i was going to do to the PROTRAIN???

Thank so much..

Team MPP

My design is the same as you are looking for. I call it Advantra.

I originally designed and flew the plane on a .46 with the sport wing and it was a great flyer. With full rates it was capable of almost every aerobatic manouvre I could think off. Never got round to trying knife edges. Not enough space at our site to do it with confidence.

The wing for the trainer version is a clark y and the advanced wing is a fully symetrical shape with a clark y center section. The prototype undortunately mets its demise when doing a very fast downwind flyby in a very strong wind. I for some reason built the wing with balsa spars (dont even know why[&:]) and the folded at about 30ft. The plane piled in to the ground (6inches under the soil) and the only damage to the fuselage was a crack in the bottom sheeting. Really proved this thing is strong and light at the same time.

I will transfer the plan to CAD this week and email you a zip file. You can even add the plan to your website to give away.

eclipsegsxr

great thanks for the help...

i'll be looking for the e-mail..
Do you have a bill of materials for it also??

one last thing where can i get a list or link to the different airfoil desings and whatnot...THe only thing I know it the semi-symetrical, symetrical, and last flat bottom wing..THe clark Y is foreign to me i Have no clue what that airfoil is..any how...

thanks again,

Brad

BMatthews

Thankyou for the vote of confidence. I'd like to think that 38 years of modelling that has been split roughly equally between my own designs and other folks plans has taught me a few things. However there's a few fellows around here that have shown me that I know just enough to fully appreciate what I do NOT know. Any of them could have offered the same observations I'm sure.

Eclipsegsxr, best of luck with your scratch built trainer. It sure sounds like Mpp's design will fit the bill. For more airfoils than you will ever use download Profili2 from www.profili2.com . You'll find the ClarkY is a flat bottomed airfoil that looks very different from what is on that PROTRAIN. Generations of modellers have trained on the ClarkY and it is renowned for it's gentle charactaristics. If it has ANY flaws it's that it can be a bit slippery in the glide and doesn't want to come down. Some nice draggy wheels willl help with that....

Obviously the world needs an easy to build trainer that flies well here on the web. Now there's a design task worth considering.

eclipsegsxr

well thats what i'm hoping to accomplish..I a nice easily scratchbuit trainer that can be used kinda dual purpose..IE..Trainer for beginners then to sport when you get more comfortable with things and only need to cahnge the Wing to achieve this...Not buy a whole new plane...

Oh well we''ll see what the future holds..

Brad

Team MPP

eclipsegsxr - I dont have a list made up for pricing materials but I will make you one up and post it. I know the original didnt cost me much and cost of materials is a lot cheaper in the US than it is in the UK. We could actually buy in bulk from the US companies and even with postage and fees the costs would be less. I should have everything sent to you by Tuesday/Wednesday at latest.

I think the model cost me around £40 including covering and accessories (approx. $60)

Bruce - I posted a couple of days ago about my new project (1/3rd Piper Super Cub). Do you know any good sites where I could find different (unusual colour schemes and maybe pictures of the cockpit arrangement). I plan to make it as scale as possible and have the cockpit controls operational with full size motion free pilot. I reckon that I can build it light enough to compensate for the extra weight involved in this. This will be my forum project for the peeps to see and hopefuly my first venture into aircraft production.

BMatthews

Other than what I could find through Google I couldn't help I'm afraid. And I suspect you've already exhausted that avenue. I've got lots of Cub model plans but nothing with any good scale info. Good luck.

eclipsegsxr

team MPP,

Cany you make sure the file format is saved it .dxf and not .dwg my chap delta cad don't like auto cad files...

I need to try and locate auto cad so i can fix this problem i have...

thanks brad

BMatthews

TurboCAD will open and save in both those formats. At least the basic Standard version will. The free learning edition may only be able to open them and then save as a TurboCAD file.

Team MPP

No problem. I do a lot of R/C car design work (we are releasing a new car this year and full engine range) and I have the same problem. I'm using Design CAD 2000 Pro and my associate in the machine factory uses AutoCAD. For some unknown reason he can only open files I send him in .dxf. Dont really like Design CAD but I got it for $10 of ebay last year. Just got Inventor 8 but now I have to upgrade to Windows XP before I can install it.

eclipsegsxr

kool thanks...

i got ahold of turbo CAD version 4 so DWG format should be good now...

Now all I need to do I figure out how to print out plane plans in full size through my lexmark 3in1 printer or the x75 normal 8.5x11 paper..I can print full size through Delta cad but not in auto cad yet.

eclipsegsxr

hey Bruce,

If I was to do some modifications on the Protrain in the areas that you mentioned do you think I with you looking things over be able to make this a better plane..And more Flight worthy??

I know have turboCAD LE and think that i can handle the mods nessecary to make this plane better...

what do you think??Is this possible?

Team MPP,
Please do still send you plane plans..I just want to fiddle with this plan abit till I get ahold of yours...I took CAD-CAM back in my high school years so Auto CAD, Turbo CAD isn't anything to new to me as I did get A 2-yr cretificate in Computer-aided-design,computer-aided-machining..

thanks all,
brad

Team MPP

No problem.

Can you tell me which program you are using to design and incorporate your planes in FMS. I have this FS but never looked into doing my own planes. I just downloaded some of the one already available on the net.

Thanks.

eclipsegsxr

Follow the link in my signature...It is my website... You'll find all the info you need on there plust the programs and even a tutorial to use the one program to make the planes...


Bruce,

I modified the tail section so far..I left the vertical alone just expanded the Rudder surface to 3" at the widest point , should I put in more rudder??

I have also increased the elevators to 2.7"

Now why do you consider a 2" thick wing to be to thick?? I'm new at this I was just wondering, I'm not saying your not right ,,I'm new to plane design so please excuse my ignorance..

Also i have reduced the Dihedral to 2" under 1 wing tip..The file in my plane section of my website in my signate has been updated with these changes..I HAVE NOT changed the Dihedral braces in the plans as I haven't figured out the Proper angles or it to equate out to 2" under 1 wing tip yet..Is this going to be enough dihedral for a trainer plane??

I think I got everthing thus far also the wing span on this Is 54"

Team MPP

Will check out the links again.

Make sure when adding dihedral that you split it evenly 1" on each wing panel or you will end up with a lobsidded wing that is shorter on one side.

There are mathmatical equations for working out the angle but I cant remember it offhand. What you can do is use your CAD to get the angle very quickly.

Draw a straightline along the length of the wingspan of one half. Then draw up 1" from there. Next draw a line between the origin point and the point 1" up. Use the angle dimension to get the angle.

Hope this helps.

BMatthews

Eclipsegsxr, you certainly can modify it to make it a better model but in looking over the plans there are a lot of building details missing. I saw enough for someone that has done a few models before but for a beginner such as yourself I would think the plans are very confusing other than as a general guide.

Airfoils- The two main areas of intrest for model airfoils are the thickness and camber. The thickness is shown as a % ratio of the Thickness/Chord. The camber, which is an imaginary middle line between the upper and lower surfaces, is an arc where the amount of arc is also shown as a %ratio of Arc Height/Chord. Not only is the PROTRAIN airfoil way to thick but it also has much too much arc or camber. The resulting shape has some drastic curves that my experience tells me will have many bad traits. If a design must use a completley flat bottom then it should be quite thin to keep the camber arc under control. It's actually much better to thicken up the airfoil by making it thick but with a lower camber line. This results in what is often reffered to as a semi symetrical airfoil. Often these are set up with a flat segment on the lower surface to aid with building on a normal board. Randy Randolph is probably the king of this type of airfoil having used it liberally on many of his designs.

I have not seen MPP's plans but if they are not complex to build it sounds like they would be a much better option rather than trying to redo the Protrain. A proven plan where the parts are known to fit to each other without unexplained gaps and where the fiddly bits have notes close by about how to deal with them are much nicer to work with. You'll have quite enough learning to do just in the building skills area without worrying about why one part doesn't seem to fit where it's supposed to.

In looking over the Protrain plans again I see that it's a good layout in some wayt but exagerated in others. What appeared at first to be a small narrow rudder is actually a TALL rudder and fin. Probably to compensate for the pigeon wing dihedral. If you want to have a go at this design here are the points I would consider modifying....

[ul][*] Change the airfoil to the one I attached below. Make the center line shown sit at a positive 2 degree angle (already shown) and modify the wing saddle area of the fuselage to fit this. You can do that by overlaying the airfoil on the plans and tracing around the bottom surface. This airfoils is on the thick side of the good range but lower in camber which should help ensure soft stalling, decent but not overpowering lift and enough drag in normal flight to hold the speed back a bit when the nose goes down. It's very similar to that Randy Randolph one. Close enough that it should fly very much like his.[*] Reduce the dihedral to 2 or 2 1/2 inches per side for the non aileron wing. You NEED more dihedral with rudder control. The yaw set up by the rudder works off the dihedral to roll the model. The more dihedral the stronger rolling action. In this area the Protrain isn't WRONG but it goes overboard and would result in some nasty habits in some flying situations. For the second aileron wing you can either make it flat or use 1 inch just for a bit of help. With the ailerons you don't need any dihedral and not having it will make it stunt a little more predictably. Not better but predictably. With NO dihedral it'll tend to fly inverted more stabiliy for example.[*] Cut down the fin and rudder vertical area by taking the top 2 inches off the plan. With the lower dihedral you don't want that much vertical tail area. It has bad spiral diving effects when it's too large and poor turn entry if too small. Along with this increase the rudder only to 2 1/2 inches wide. It's already 2 inches which is close to what you want. The extra 1/2 will certainly make it large enough and if it's too much you can just cut down on the rudder travel.[*]Leave the elevators alone. They are big enough. In fact when you set this model up for training do not use more than 1/2 inch TOTAL travel as in +- 1/4 inch. With the 2 1/2 wide rudder I would set it up for +- 1 inch for the first flights. That assumes you are using an instructor. IF you are training yourself (not recomended) then use +- 3/4 only at first.
[/ul]

Here's the ribs I would suggest. If you would like I can email you the DXF files......