View Full Version : Dewoitine D-27 Project
Hi all, especially Dave, Jim, Chris3D and Bulent...
Since a few weeks, after seeing Dave's Brownie, Chris's MicroMoth & MicroPitts and discovering the possibilities of the RFFS system, I' ve decided to do a first attempt in that tiny scale by scratchbuilding a Dewoitine D27. I know I didn't choose the easiest model :rolleyes: (round fuselage, etc.). See pictures on Ghmbo's Scale Quiz" (http://www.radiocontrolzone.com/forums/showthread.php?s=&threadid=91473&perpage=25&pagenumber=2)
Having not a lot of experience, I have drawn a virtual model of the plane (3Dsoftware: Maya). Now I will ask for advices ;) , I join some pictures of the results. I will take any suggestion and adjust my virtual model still the "right solution".
I hope this thread will help to share ideas on that tiny scale and maybe create some vocations. And why not more "race results (RFFS-100) racing (see Dave's Robelen last thread) in a near future...
Having not too much time for my hobby at the moment, I will ask for patience :)
Specs.:
wingspan: 16.53 in. (42 cm.)
wing area: 45.6 sq. in. (294 sq. cm.)
weight: between 25 and 30 gr (?)
Picture 1/3: two differents views
Frederic
Picture 2/3: "classic" 3 views. My model isn't at the exact scale but not too far... I worked on a 1:10 plan of the real plane made for the wind tunnel tests.
Picture 3/3: removable part for access to the equipment. The wing is also removable. The presented solutions are not final. But those pictures are a starting point.
To build the flying model, I already bought 1/32 and 1/16 balsa sheets. One basswood sheet. Music wire: 0.020" and 0.015" diameter. I will probably install 2 actuators (Bob Selman's ones or DV modified (Dave's solution) near the CG with pushrods.
Currently, I haven't the RFFS system and will have to buy it. Hope it will fit in the fuselage :rolleyes: Maybe I could be the 500th buyer :D
So now I'm waiting for your suggestions:
- number of ribs for the wing?
- how to fix the wing (magnets or not)?
- how to do light "hinges" for the tail and rudder?
- azarr antenna?
- flat rear bottom for the fuselage?
- which struts to reinforce?
- less details or more?
- how to fix discreetly the wheels?
- a ailerons solution for a second plane?
- etc.
Well that was some ideas...
Frederic
GHMBO
10-20-2002, 12:01 AM
Hi FLB
I am taken back by your graphics. It appears that you engineering/design is well thought out. The difficult part is getting the fuselage built with all the compound curves. The traditional methods would be to plank and use balsa blocks. Since the model is small, I would look into vacuum forming the skin out of .020 ABS (or thinner)and attach to a very light structure. Maybe others have suggestions. This Micro stuff sure pushes the envelope of construction. Keep us posted on your progress.
Jim
Hi Jim,
Glad to read you. You see, you gave me the taste to scratchbuild something. :D
For the compound curves, I've got an idea but I'm still not sure that it will work. I designed the virtual model as I wanted then with my 3D software, I will take the dimensions of the 3D forms (arc length) and apply them in 2D. I already start to do that but haven't cut balsa or paper to verify.
Unfortunately, I never try vacuum forming and have no experience and no equipment to do that. So I will certainly stay in the traditional way as Dave with his Brownie and Chris with his Moth, Pitts and now Fokker DR1...
Best regards
Frederic
Dave Robelen
10-20-2002, 10:38 AM
Hello Frederick,
Those graphics are truly amazing. It sounds like the solutions you are proposing are in the best direction. I would suggest turning the power unit around in the nose so that the large gear is in the rear. This was a big help in the Brownie with it's slender cowling. I put one 1mm ball bearing ( Dave Lewis www.homefly.com) in the tip of the nose to support the extended shaft.
If you have the facilities to carve a solid fuselage, it is very possible to "mold" balsa sheet in sections to create the compound curves. The Top Flite company used this method some years ago in a series of WWII control line models. If you are planning a thin sheet wing, I would use no more than two ribs on each side of center to preserve the airfoil.
You have chosen a challenging subject, good luck with it.
Regards, Dave
GHMBO
10-20-2002, 02:21 PM
Dave
Boy-oh-boy, you jogged my memory of the old Top-Flight models. Jim Walker used to mold the airfoil in his dime gliders.
FLB
With the current 3D and CAD software, sheet-strip planking should be a snap. I can recall building a P-39 that had sheet planking. The planking was cut from sheet balsa and started narrow at the nose then wide at the mid fuse and narrow at the tail. It took about 8 planks per side. The planks were moistened for the minor compound curve. With computer generated x-sections and precision curve lengths, the planks can be easily drawn. I would consider building the fuse in halfs with top and bottom keels. The planking can be applied while the half is on the plan then joining them.
Jim
Hi Dave and Jim,
Thanks for the comments.
When I saw the Bownie's power unit, I tought I will do the same for the D27 but I didn't remark that you have used a 1 mm ball bearing (thanks for the link) and that the motor was turned around ... important details :rolleyes: Where can I found a correct power E-Charger motor? If I buy a standard RFFS-100 complete system with a KP00 motor and a U80 prop will that be sufficient? Or will I have to do my own gear system?
Concerning the fuselage, I modelized the plane in my 3D software to obtain the cross sections and the dimensions of the planks. Don't know now if it will be enough without too much adjustements... I think that I will do a test with paper or cardboard as soon as my drawings are done.
Regards
Frederic
Dave Robelen
10-20-2002, 10:29 PM
Hello Frederick,
The E-Charger motor is physically identical to the KP-00 in dimensions, but a little less powerful. It has been my experience that the small U-80 prop is not adequate for the weight and drag of a scale model. I purchased the E-Charger toy at WalMart here in Farmville. It is probably better to use one of the 6-1 DIDEL gear units with the KP-00 motor as sold by DWE. This would drive a GWS 5-4.7 prop very nicely.
Regards, Dave
Hi Dave,
Thanks for your suggestion. I will keep itin mind.
Here are some more pictures. One on the actual internal structure (grey balsa & black music wire). This is not definitive.
and a idea for a "suspended" landing gear if necessary...
Regards
Frederic
Dave Robelen
10-20-2002, 11:02 PM
Hello Frederick,
Boy, your techniques of ilustration are outstanding. I would go with the rigid structer built from .020" wire. With the very low landing loads of these light models, shock absorbtion is not all that necessary. I wrap my joints in this wire with a strand of copper wire taken from flexible stranded lamp cord and solder with regular electrical solder. So far, so good.
Regards, Dave
dhurd
10-21-2002, 08:42 AM
Frederick,
You may want to consider using CF rod as opposed to music wire. Music wire starts getting heavy in a hurry.
Dan
flyinhigh
10-21-2002, 07:24 PM
Heya FLB
Jeeesh you had me confused for a minute.you were talking about building this plane.then the pic of the plane pops up:confused: Those graphics look real Im planning on starting a RFFS project but nothing like that lol Really good planning you got there FLB
Take Care and hope everything comes together nicely
MIKE
flyinhigh
10-21-2002, 07:31 PM
Oh Yeah
About music wire..you are planning to use??Isnt there anything else lighter than this stuff.Like Aluminum ever since I weighed music wire I been trying to find a way to get out of using it.Any Ideas ??
MIKE
Hi all,
Dave,
Thanks for the solder tip. I went on DWE website to see a 6-1 DIDEL gear units with the KP-00 motor and I saw two 5-1 or 6.6-1 Didel gear units but no 6-1 one... What will you recommend between those two ones?
Dan,
I was also considering to use CF rods but for me CF rods are harder to find than music wire. A mix can be conceivable. I saw that you sell somes ;) I'm already affraid :D for my future bill.
What weight for your micro antenna?
Presently, I'm doing an extra contract which take most of my time after work and seems to me to be endless. :rolleyes: So to found some motivation, I decided one month ago to buy my RFFS system with the money I will earn there. I hope you will not have to wait too much :D Each evening and week-end I'm divided (?) between my D-27 project and this contract...
Mike,
Like you I plan to start a RFFS project a few weeks ago after seeing Chris's MicroMoth and MicroPitts. Most of what I heard about the RFFS system is very positive. I know that I haven't choose a easy model but with this tiny scale experimentations do not cost a lot.
Hope your Mountain Models Cessna 180 goes well...
Regards
Frederic
Dave Robelen
10-21-2002, 09:37 PM
Hello Frederick,
Normally I would be on the bandwagon for carbon fiber, but the weight of .020" wire in these small quantities is really quite small. When you add the strength you can achieve by binding and soldering the joints in a complex shape, wire looks real attractive.
Dan, I heartily agree that CF is lighter than wire, but in the .016"-.020" range, small quantities of wire have a very modest weight. The ease of shaping and assembling some of these scale gears makes the wire even more attractive. Adding balsa fairings ala the Brownie provide the needed scale appearance with good strength.
Cheers, Dave
Hi Dave,
I agree with you that music wire is very interesting in my case because of the complexe shapes I draw. For sure 0.020" and 0.015" rods seem to be so light in my hand but I haven't weight them. By the way, my wire structure is maybe too important. I will see if I can refine it to do it lighter with a mix of balsa, basswood, music wire and CF.
Thanks for all your advices. :)
I'm searching for a special tip: how to fix wheels lightly?
Frederic
Dave Robelen
10-21-2002, 10:45 PM
Hello Frederick,
If you are reffering to keeping the wheels on the axle, my method is a small bead of cellulose glue on the axle wire end.
Regards, Dave
Hi Dave,
That's clever as usual. I always think about big stuff because of my previous and little experience in bigger models but I will definitely try it.
Frederic
Hi all,
For those interested in scratchbuilding micro planes from 3 views, here is a link to Digital card Models website. On this site, you will find small models to buy, some free and also a free version of a software which can convert a simple 3 views in a plan with cross sections (Plan-Maker software, approx 2.75 MG). I haven't try it yet but seems interesting.
http://www.ww1cardmodels.bizland.com
Frederic
bmutlugil
10-22-2002, 03:53 PM
Hi Frederic,
Your project looks very interesting, and your drawings are amazing.
Planking may be a good way of implementing the fuselage, but it has to be done carefully. I used planking for the turtledeck of the Sperry, but this had a simple curve. As suggested before, was it Jim who said this, by changing the width of the planks along their length, you can produce compound curves.
I don't know if a foam fuselage covered with very light glass cloth (or other fabric) and epoxy resin could be an alternative at this weight level - I do not have experience in very light models. You can remove the foam later, by dissolving it with a solvent :D, but putting formers in the fuselage could be a problem.
I had seen photos of models with molded balsa forming fuselages halves. You require a positive mold on which you can shape the balsa sheet softened by soaking in water (or ammonia), using strips of fabric to wrap it on the mold.. Don't you have shops in your vicinity where your 3-d fuselage halves can be shaped by CNC?
As for the landing gear and struts, I say go for the wire.. I made my wheel hubs a press fit on the (1 mm steel) axle wire, which rotates with the wheels - very simple and easy to remove.
Good luck, and keep us informed of the progress..
Bulent
Hi all,
Bulent
Nice to read you there ;) Unfortunately, I'm not able to imagine your press fit system... Can you show me something or explain it one more time, please.
I will certainely use the balsa planking method for the fuselage. I will try to keep at the minimum (2) the number of balsa planks. Experimentation with cardboard, paper or balsa will orient my work.
Here is the simple method I want to use. Since the plane is all modelized at the right scale, I will just have to take the measures of the cross-sections I built. I have an arc lengh tool in my 3D software. Then I will report all my measures on 2D. I join a picture for a better understanding. It's the third cross-section. I put 3 markers to show some possibilities: first one at the beginning, third one at the middle point and the second one in-between. I obtain directly the distance in centimeters (in my case).
Regards
Frederic
And here is a "rough" try for an 2D half side of the fuselage...
Frederic
p.s. hope all these pictures will not be too long to download for those who have slow modem connection :(
KSU Flyer
10-23-2002, 12:15 AM
what software are you using?...very nice!
Hi KSU Flyer,
I'm using MAYA from Alias-Wavefront. Great software:
http://www.aliaswavefront.com/en/products/maya/index.shtml
Too expensive just for a hobby even if the price has drop few months ago. I work with it all day and for me the D-27 project is a "relaxing moment" ;) Hope at the end this plane will not be just virtual :D
Regards
Frédéric
Mike-KSU FLyer,
One 3D software I would consider for my hobby if I haven't Maya would be Turbocad. Seems to be simple and with a lot of possibilities. There is also different versions:
- TurboCad Pro (499 $)
- TurboCad (99 $)
- TurboCad LE (free)
Two links for that:
http://www.turbocad.com
http://www.imsisoft.com/free/
I tried the 15 days free version of TurboCad Pro few months ago. Not working as my Maya but was interesting. For sure, you will have to "work" if you are not familiar with that but could be nice too.
By the way your Dumas Bearcat is great in pictures and in flight. I just watched the video a second time.
Regards
Frederic
KSU Flyer
10-23-2002, 09:36 PM
FLB,
Thanks for the heads up...I've heard a lot of folks praise TurboCAD, I'm sure it's great. I actually graduated from a technical college as a technical/mechanical CAD drafter back in 95. I was introduced to AutoCAD R12 and have kept up the the incremental releases since then. Since then I've also learned to be pretty proficient with PRO-E, Solidworks, Mechanical Desktop, and Inventor (all parametric solid modeling packages). MAYA, seems to be more graphics intense, than a mechanical part designer? Anyway, it's always cool to see someone that enjoys computer modeling as much as I do. Can you save your models as a ACIS solid (.sat) file? If you're having trouble getting the 2D views from your model I might be able to help. I'm glad you like the Bearcat...I have to tell you...It flies as good as it looks. Good luck with your designs. Keep me/us posted.
-Mike
Hi Mike,
I'm happy to see that you are in the 3D field.
Sure that if you can work with Autocad, go with it. It might be the best for that kind of think. I'm not a technical CAD drafter. I work for publicity, more for effects and some modelizations which must look like... but are not exact CAD design. I know AutoCAD R12, PRO-E and Solidworks but never works with. MAYA big difference is essentially its animation possibilities. This software is so powerfull that every day I tell me I will never master it completely. It's an utopian idea. In my case, I do all (modelization, texturing, animation, lightning) but usually you work with a team where each person has a speciality. Limits are not anymore in the medium but in the head (lack of imagination...).
I don't know lot of people working in 3D and building RC planes. But few weeks ago, I discover that Chris (Chris3D), who did the MicroMoth, the MicroPitts and works at the moment on a micro Fokker DR1 and an microfan, is also in the 3D field. He is a great artist. Here is a link to his website: www.chris3D.com
The finish of your Bearcat is so nice... I see that your Bearcat project prompts Sootall to do one. I think his one will be nice too.
Regards
Frédéric
flyinhigh
10-23-2002, 11:04 PM
Hey FLB
Thanks for the program links,I downloaded the modelmaker program and found that you already have to have good 3veiws of the plane,it scales it for you from that.Its confusing me at the moment but will soon get a hang of it.The cad programing is what Ive been wanting and but was a bit pricy when I went to Staples to look at it.I was totally unaware that they had cheaper versions or even a free one:D All I need it for is to make plans for airplanes.do you have any Idea if the Turbo or the LE version would be acceptable for this??Thanks for sharing your wisdom with us,you may be saving me room from getting a drafting table setup:rolleyes:
Take Care
MIKE
Hi Mike-flyinhigh,
You are right you need a good 3 views of the plane fefore starting. Here is my favorite link for that:
http://www.simviation.com/3viewand.htm
About a software to draw planes plans, sure both TurboCAD version will do the job. In fact, just for a plan you need a 2D software. Few weeks ago, Ghmbo gave a link to a free 2D version (older) of TurboCad. I downloaded it and try it a little. I think you can start with it if you don't want to buy one. Otherwise the TurboCad LE (light Edition) at 99$ must be enough for drawing plans. I think the difference between TurboCad Pro and LE is that with Pro you can work in 3D and do some renderings (pictures in 3D).
Here is a link to see what Ghmbo did with TurboCad:
http://maryjo3.freeyellow.com/index.html go to Electric Model plans and bottom page see the Bristol Scout, the Sopwith Pub, ... , Nieuport 17 and Thomas-Morse 4C.
Regards
Frédéric
Hi all,
Today I 've got an idea to help me gluing the fuselage planks and cross-sections. It must already exist but here is how I plan to do it.
Each cross-section will have four little "tongues" which will pass through some corresponding holes in both fuselage flanks. That way, I hope to be able to glue all that stuff correctly even if I can see the fuselage's interior. After drying, I will sand these tongues until they "become part of" the fuselage.
Well a picture will explain all that (I haven't reproduced all the fuselage on that illustration):
1- flat fuselage,
2- balsa is bend,
3- cross-section and flank are glued together,
4- finish after little "tongues" sanding.
Must be nice with a laser cut machine...
Regards
Frédéric
Hi Mike-flyinhigh,
Here is the link to the free TurboCad 2D I was speaking about earlier:
http://www.modellbauerauktion.de/dxf_files/
Click on > Turbo Cad LT (7,35MB) <
Be aware that the download could take time.
I just saw that there is also a lighter software on the same page > RC-Cad (3,19MB)< . Now it's up to you to try all that ;)
FLB
KSU Flyer
10-24-2002, 10:52 AM
Something for thought...
Have you considered using fuselage stringers similar to that of the Dumas Bearcat? Might be easier than trying to come up with all those flat patterns.
-Mike
Hi Mike KSU Flyer,
You are right conventional method with stringers will be easier altough I'm not sure it will be lighter. But... ;) in this case, it's just to experiment something different after having seeing Chris's MicroMoth and MicroPitts. I hope at the end the round fuselage with flat patterns will be nicer than if I had choose the stringers solutions. I'm not press by time. Thanks for your suggestion.
Regards
Frédéric
GHMBO
10-24-2002, 04:21 PM
Hello FLB
I know that at this point that you are worried about the fuselage skin and are looking at internal structure. Since you will have to mount the electronic equipment, the e-shelf can be made part of the structure to hold some of the Fuselage formers in alinement. Thus the skin tabs will be needed only on the aft formers. I used this scheme on a Cessna L-19 that I have drawn.
Jim
Hi Jim,
Thanks for the suggestion. You're right and I will think more on that e-shelf. It could also help me to build correctly the caban struts. Well I will draw something...
About the Cessna L-19 is that the one you was talking about in an earlier thread, a L-19 birddog? Will be curious to see the plan ;)
Regards
Frédéric
Hi KSU Flyer,
I just read one more time all the messages on this thread and I saw that unfortunately I miss a part in your second message when you talked about transfering 3D measures in 2D. I can not save in .sat format. But here are my different possibilities:
.obj, .rib, .iges, .dxf
Maybe we could try something... :)
Regards
Frédéric
GHMBO
10-25-2002, 03:39 PM
FLB
Cessna L-19 Birdog plans are in your mail. Let me know what you think of them. I still am learning TurboCad and am moving into 3D at a slow rate. One of these days I hope to acquire some of the skills that you have displayed.
Jim
bmutlugil
10-25-2002, 05:30 PM
Hi Frederic,
The wheels I built were made of laminated balsa sheets (3 sheets of 3/32"), cylindrical hubs of 4 mm. dia and 9 mm. length were turned from glass reinforced plastic and glued to the center. I drilled the hub plastic using a 1 mm. drill, as the axle to be used was this size. Unintentionally, because of the nature of the plastic, the holes were smaller, so the wheels could be pressed on the wire only with some force. I decided to use this to my advantage, and arranged the axle to rotate with the wheels as a single unit. This was easy in my landing gear, as the struts are carbon - I just drilled 1 mm. holes in the struts .. This can be done with steel wire landing gear also, by forming loops in the wire where the axle is to be placed..
I use o-rings for tires. I hope this is clear.
Best regards,
Bulent
Hi Jim and Bulent,
Jim,
Your L-19 plan is really nice and clear. Great job. Your e-shelf idea is good and I will use it too. I saw that this time you have integrated the magnets solution to fix the wing. Your plan is also a great explanation of your skin tab and aft formers solution you was talking about. It's really a professional design ;) Did you plan to offer it on the web as some other ones? Otherwise we will maybe never see one flying. It would be sad...
I'm glad to hear that you are moving to 3D. I don't worry with your 2D skill. If you have any question, don't hesitate.
Bulent,
This time it's very clear for me. Thanks for your new explanation. I will retain also the o-rings for tires solution. I think Jim used it also.
Thank you both of you for your suggestions.
Regards
Frederic
flyinhigh
10-25-2002, 10:50 PM
Hello all
Looks like your coming along FLB.getting lots of good ideas I see:D
I am going to post this program here just in case some of you had forgotten about it or had never seen it but is a good airfoil program.Ive had it for a while but never registered it which I may do here soon it dose 3d well sort of and will also let you desighn fuse's on it,well Ill let you all read about it here is the link
http://www.winfoil.com/winfoil/overview.htm
Have a good night everybody
MIKE
Hi flyinhigh,
Thanks for your input. I never try AirFoil but I will maybe download it to see how it works.
How is your Mountain Models Cessna 180 going?
Frédéric
flyinhigh
10-26-2002, 12:27 AM
Hey FLB
Well the Cessna got side tracked even though Im on the last bit of covering,the front underside has gotten me pullin hairs out,and I need all my hair...I know I shouldnt have started another project but I did,Will work on the Cessna soon though and get pics of the Tipsy Nipper up as soon as its ready to cover.
Hey you can load the airfoils into your CAD programing too I thought that was a great feature.
Happy Desighning :)
MIKE
mike nill
11-04-2002, 12:33 PM
huuuuuuryyyy up:)
Hi Mike Nill,
Thanks for your direct encouragements :D but I think I've never worked so much in my life, days, nights, week-ends and I don't even see the end :( . As you must have understood, no time left for my Dewoitine project. You can not imagine my frustration :mad: But I'm still there with a lot of motivation, just waiting for free time.
In fact, it's not so bad. Dan from DWE continues to upgrade his stuff and products, and Dave shows us one more time with his new P-Nut that this tiny scale seems to be really great with the RFFS system ;)
I'm improving my patience and yours too :D
Regards
Frédéric
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