My entry into the Wattflyer Scratch building contest #2

Joe Colletti's DH-88 Viewed 192 times

[starcad]

OK, I see WattFlyer is running a Scratch building contest.  Can I resist?  Heck no   I've been looking for a design to build for several weeks and finally settled on a Beechcraft Bonanza, yep!, complete with the V-tail.  So, Sunday I sat down at the computer and decided what I wanted the plane to be and do. It had to be easy and quick to build.  I had to be balsa as I haven't had balsa dust in my lungs for awhile.  Most of all it  had to be electric for the sheer ease of going t to the field and flying.  Flight performance wise, I wanted something scale looking but not to the point I'd be afraid to fly it.  Fast but able to slow down for scale like landings.

Back in 1997 I designed the Cherokee 140 Profile.  That plane almost became a kit.  It is a blast to fly and really easy to handle as it is all one piece, wing and fuse are joined.  It's a profile and very simple to build as the wing takes about one night to complete if you have laser cut ribs.  The Beechcraft fits well into this type of design, so my hunt was on for a good three view.  I found what I wanted in a jpg image of a plan and used that profiles numbers to input into Visual Model Calculator coming up with numbers that I could work with.  After three hours drafting in Drawing Board I had a rough draft sketched up.  After two days now I think I'm ready to port the drawing over into AutoCad for final finishing of the design.  I plan on buying the wood this weekend and should have the ribs cut and shaped with a partial layout of the design.  Next comes the parts checks and the final version of the concept design.

 If all goes well and hopefully I won't get tied up re-writing another tech manual, I should have it ready for maiden in about 4 weeks.  My granddaughter takes a lot of my time as I never thought I'd be raising another kid at my age.  So, if I miss a couple of days please forgive me.

[starcad]

I was able to get some more drafting completed this week on the Beechcraft design.  I'm still considering how to work out the tail and the nose of the model.  I've been considering cowl cheeks to hide the ESC but haven't been able to come up with that prefect design just yet.  I need something with an opening to allow the air in and a way to allow the air to escape but so far I haven't been able to conceive it in my mind.  I've been pondering my old control line days and the Carl Goldberg Shoe String design that had a cheek to hide the fuel tank.  That was really a clever idea back then and I've been trying to come up with some sort of way to utilize that idea into the Bonanza.  So far the wing design is almost complete and all I have to do is draw out the battery hatch and add the servo rails along with finishing the construction details on the drawing.

Anyway, I plan on cutting out a mock up with fan fold tomorrow to get an idea of radio placement and other goodies.  The mock-up will also serve as a way to locate the C/G and check the also check the calculator. 

I'll post some images tomorrow and also add a post to Wattflyer.

[starcad]

OK, No images but I've almost finished the drawings for the fuselage and am tiding up the drawing a bit.  So far it really looks good and I have to stand back and look at the printed output and admire the design.  I still have a bit of work to do on the wing but for the most part that part of the design is finished.  It's funny how you get to a point and then you have to just start cutting wood to get everything set on both the plan and in your mind how it is going to work.  I will try to get some images up tonight but I really want to concentrate on cutting out a fan fold version to check the C/G an radio equipment locations.  Also, I have to figure out how to program my Futaba to Eleavons or V-Tail mixing and still be able to have a rudder servo I'm thinking maybe a y-cable or some other mixing.  Time to dig out the manual and do some reading on the subjects.

Later - Guy

[starcad]

Not much to report tonight.  I took my grand daughter to her Karate lesson and time just went by.  I find it funny how in my younger years with two kids to raise how much more time I had back then compared to now.  One young one takes so much more time than two did 25 years ago.  Back then I was running a software business and working full time.  I still had time to build and fly models.  Now I work full time but have little time for models.  I also find it funny that after raising two kids that I now find myself having to go to Parenting Classes twice a week to learn how to raise a 6 year old. 

I should be able later this week to get some images on the forum and also some data on the design. I can tell you that the Fan Fold concept cut out really looks neat, even for a FFF profile.  I still have to work out the nose gear steering along with the killer V-Tail but I believe with the cut out I should be able to solve and over come those problems.

[starcad]

Ah! construction started, well almost.  I still have the problem of the dihedral brace and the battery box in the center section of the wing.  This must be why I love scratch building and one always needs to find ways to over come obstacles.  I find it very stimulating trying to come up with a simple yet effective way of accomplishing some simple.  I may be over thinking this but I'm not sure.  Ribs have been cut and the only thing holding me back from having the wing  built is the fact that when I went to the LHS I forgot my list.  Forgot to pickup the 1/16 X 1 that will be the trailing edge.  Oh well! Just another trip to the shop so when I go I will also pick up the wood for the fuselage.

Images!!

[pburt1975]

hope ya dont mind me following along here too, Starcad

[starcad]

hope ya dont mind me following along here too, Starcad

Not at all.  Kind of a set back today and I think I'm going to have to revise the wing again.  I trial built a wing today out of some scrap balsa to see if I could figure out how I wanted to build in the dihedral brace.  Well I should have had another cup of Jo as at 5:00am I really don't think very well.  I messed it up pretty good but learned a lot and enough to know I really need to be awake and aware of what I'm doing before I start cutting and bashing balsa.  Anyway I didn't use the new wood so It's kinda back to the drawing board and clear up some more of the design.  So far from what I've seen in the build it will be both a very flyable and durable design, kind of one of those planes that you fly every weekend.

I really like the design and so far it looks very promising and should be a real winner but, like all designs it just needs to be worked out.

[starcad]

Well, deep subject, I started building the new wing design today and it is going together better than expected.  Don't get me wrong, this is a hard wing to build with the airfoil I selected.  The dihedral brace worked out this time and everything seems to be fitting just as expected.  First image is of the whole wing.  I still have to add the leading edge caps, center section, along with the gear blocks and servo trays.  Second image is the dihedral brace that finally worked out so far.  I will probably start on the fuselage tomorrow and try to finish up the wing as much as possible.

[starcad]

Wow! Got a ton of things done today.  All the major parts for the fuselage are cut out along with the internal like the nose gear bearing and the motor mount.  This is really turning into a challenge as there are really no examples of how to build and design something like this plane.  The wing is basically built and the tail is cut out along with the elevators.  Assembly  should start this week and end this coming weekend.  Pictures later tonight or tomorrow.  I think I still may have a few more hours of designing to do to get the final version.

StarCad

[starcad]

OK more build pictures.  All the major parts cut and ready for assembly.  Just have to add the center section channels for the wires and the cut-outs in the rear for the tail servos.  I plan on using five servos and hope my esc can handle them all. 

[starcad]

Wow, a lot accomplished in the last two days.  The wing is almost complete and I was able to get one of the landing gear blocks built today while working on the inner fuselage structure.  As with all new designs, it's the little things that keep popping up that slow down progress.  However I think that is the best part of design being the unknown what ifs.  So far I've been able to overcome all the obstacles this design has involved and now I'm looking almost at the end of the concept of design.  I haven't had to draw or re-draw anything in the last several days and that is a good sign. All the parts fit just as conceived and it seems that all the pieces of the puzzle are coming together to form a model airplane. 

I should have pictures up sometime tomorrow night - stay posted

[starcad]

A lot more building this weekend.  The wing is finished and rough sanded and I worked out most of the fuselage today.  I should have it ready to stack and join later this week.  Bent and formed the landing gears and found my long lead servos.   Just ran out of model building steam today so I though I'd just set it aside for a few hours.

Tomorrow afternoon, when I get back from work, I'll work on the center section of the fuse and add the motor mount and the nose gear blocks along with the nose gear steering arm.  I should have the wing final sanded and the first part of the covering on later in the week.  I'll try and post more images tomorrow as it's getting late and I have a 5am curtain call.  So that means I have to be up at 3:30, Ugh!

[pburt1975]

Coming right along I see.  Whats your final attachment between the fuse and wing going to be?  I need ideas for the electra,

[starcad]

Well, being this is a profile design, I will probably cover the wing and the fuselage and then just slide the wing in place and epoxy.  I have to take care of the internal wiring before final assembly so that all the servos, ESC, and battery wires are in place before adding the final layers of the design.  I will probably finish building the fuselage this weekend and then start covering.  Still have a ton of work to do on it but I think everything is ready for assembly.   

[starcad]

OK, light at the end of the tunnel I hope. I was able to get a bunch completed this week and today. I have one cut-out left on the wing and should have that done tomorrow along with the ailerons shaped and sanded. The 1/16" sides have been laminated to the frame and the nose gear installed. I rough sanded the outline early this evening and will add the ply doublers and the 3/16 doublers tomorrow. I need to open the wing slot in the fuse some more to fit and then I will be on to covering and finishing up. Hopefully I should be ready to fly next Sunday or Monday and the World will know if it goes or fails. That's one of the things I like about model design, you never know until it flies. Colors will be Maroon on base White with a gray strip and black registration numbers.

I haven't taken on a project like this in several years and it has really been a trip down memory lane creating new ideas and addressing different ways to achieve the desired concept. What a neat journey from concept to product.

Pictures to follow tomorrow as I want to upload a few.

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