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Old Oct 05, 2012, 09:19 AM
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Hey Ken...was wondering if you've had anymore thoughts on the ruling of delta wings...the 150 sq. In. rule isn't feasible as the plane will be to small...how about just setting a fixed wingspan to somewhere around 21"-24"?..I don't think there will be any advantage to allowing more wing area on these planes...I have an Su-37 profile that flies great on elevons with a wingspan of 21"...here http://www.rcgroups.com/forums/showt...803385&page=23 post #331...this model was deigned by tomhe here on rc groups
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Old Oct 05, 2012, 09:20 AM
Danish? Don't U eat that??
DKChris's Avatar
Denmark
Joined Jan 2008
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Did a couple of crude calculations to try and check my thoughts on CG; I used approximate sizes directly from the drawing, so the calculations won't fit ken's model with 10% larger stab.
Much to my surprise the 2 calculations come out quite alike.........at about 25-30% of the chord.

The calculator for Cg with stab is on: http://www.geistware.com/rcmodeling/cg_super_calc.htm

The flying wing CG calculator is on: http://fwcg.3dzone.dk/


Might be interesting to see how ken's experimentally found CG on the Hunter fits the 2 CG calculations.........
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Old Oct 05, 2012, 09:48 AM
Slipping the Surly Bonds
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Quote:
Originally Posted by planecrazy1969 View Post
Hey Ken...was wondering if you've had anymore thoughts on the ruling of delta wings...the 150 sq. In. rule isn't feasible as the plane will be to small...how about just setting a fixed wingspan to somewhere around 21"-24"?..I don't think there will be any advantage to allowing more wing area on these planes...I have an Su-37 profile that flies great on elevons with a wingspan of 21"...here http://www.rcgroups.com/forums/showt...803385&page=23 post #331...this model was deigned by tomhe here on rc groups
I am liking the fixed wingspan idea. How about the limit being all parts fitting into the 24" x 48" sheet of foam. This will put material available limits into the designs while allowing the designer some additional freedom when it comes to deltas. Can you get your SU-27 into a single sheet?

So far, both the Hunter and Vampire fit into single sheets.

Ken
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Old Oct 05, 2012, 09:55 AM
Phantom Mechanic
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How about and F-105? That bird is long but narrow!
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Old Oct 05, 2012, 10:27 AM
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Originally Posted by dz1sfb View Post
I am liking the fixed wingspan idea. How about the limit being all parts fitting into the 24" x 48" sheet of foam. This will put material available limits into the designs while allowing the designer some additional freedom when it comes to deltas. Can you get your SU-27 into a single sheet?

So far, both the Hunter and Vampire fit into single sheets.

Ken
I know I didn't get any response from my previous posts, so maybe you are busy? But here goes another thought and I some feed back good or bad is quite fine because I have the same questions as PC1969 so I am sure others do too?!?!......

If for some reason if my thinking or questions are completely off base, let me know and I will stop asking my questions and move on.

The fit a 24"x48" sheet idea is good, but has a major flaw. I think asking most potential designers or RCG members to reverse engineer everything until it fits a certain sheet size is asking too much. Not everyone does Sketchup, or can easilly transfer a 3 view to a sheet of a given size. Cooperation should include something the masses can accomplish with simple straight edge and knife, using a simplified size rule.

If you set a wingspan as PC1969 asked for, then most builders can start with drawing the wing, and probably then fit the rest of the design to a sheet. I personally don't plan on selling kits, so if I use more than one sheet, or can get some cuts from scraps I will do such a thing. Not everyone will have MPF to work with anyway, and we know that some kinds of foam need to be wroked different to get things to fit a design.

That being said, a 21-24" winspan on Deltas sounded reasonable to me as this will fit your intended sheet size limit for span, and most delta's are not so long anyway. I am guessing this will net some 200 to 250 sqin wings, but they will suffer from drag, so an advantage over a different layout may not be a big issue.

Of course one of those previous posts that I didn't hear any response on was picking a scale size. Take any airplane, look up the specs (Wikipedia works for that most of the time), multiply the full size airplane wingspan by the scale factor, and you have the size of the model to make. Now all airplanes would look right next to each other, and probably fly similar to each other as the real birds do in real life. Proportionate.

If a Mirage 2000 has a 29 foot wingspan, and we made it a 18th scale model...... 29x12 inches = 348 inches. 348 inches divided by 18 (th scale) = 19.33 inches. At 14th scale then the model would be 24.8" wingspan, etc, etc. Thinking out loud again, swept wings, and all other forms of jets makes picking just a wingspan range tough, because a Mig 17, or BAC Lightening could be huge using just a wingspan range.

Last, where do you put streamer on these pusher designs? If they are combat models they need streamers, and the streamers would normally mount where the propeller is??????
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Old Oct 05, 2012, 11:12 AM
Slipping the Surly Bonds
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Fred,
I value your input and apologize for not responding to your question and comment.

Quote:
The fit a 24"x48" sheet idea is good, but has a major flaw. I think asking most potential designers or RCG members to reverse engineer everything until it fits a certain sheet size is asking too much. Not everyone does Sketchup, or can easilly transfer a 3 view to a sheet of a given size. Cooperation should include something the masses can accomplish with simple straight edge and knife, using a simplified size rule.
I am in agreement with this concept.

Just started collecting wingspan/length data off of Wikipedia. There is so much variation that this is going to be a tough nut to crack. Still noodling this.

That is why I am building a few designs, to get my head into this and find what works.

The streamer question; alternately full contact.

Ken
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Old Oct 05, 2012, 12:03 PM
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Originally Posted by dz1sfb View Post
Fred,

I am in agreement with this concept.

Just started collecting wingspan/length data off of Wikipedia. There is so much variation that this is going to be a tough nut to crack. Still noodling this.............................
Thanks and I do understand. ---- -----



Quote:
Originally Posted by dz1sfb View Post
The streamer question; alternately full contact.

Ken
Wow would that be fun. I could get into that. Not sure on AMA clarification, but hard hat recommended...... Maybe some further researce into the Sconic Combat Module is needed.
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Old Oct 05, 2012, 12:10 PM
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Early drawings of the f-100...148 sq in wing area gives it a 26 in ws...motor will have to be mounted in back...fuse is to narrow for a center prop in slot...it is designed with elevons and the elevator root chord has been enlarged 10%...to fit this plane on a 24"X48" single sheet might be challenging, so a VLF version might be more fitting...on the streamer issue...is it possible to attach it to the top of the rudder?..or would this mess with the planes flight characteristics?
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Old Oct 05, 2012, 01:02 PM
Slipping the Surly Bonds
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Originally Posted by planecrazy1969 View Post
Early drawing of the f-100...148 sq in wing area gives it a 26 in ws...motor will have to be mounted in back...fuse is to narrow for a center prop in slot...it is designed with elevons and the elevator root chord has been enlarged 10%...to fit this plane on a 24"X48" single sheet might be challenging, so a VLF version might be more fitting...on the streamer issue...is it possible to attach it to the top of the rudder?..or would this mess with the planes flight characteristics?

I love the look of the F-100.

I thought of the top of the rudder, but adding the streamer drag to that point will cause a perpetual pitch up characteristic. If you trim for it then a cut can suddenly put you in pitch down mode.

1/16 scale or close to that is looking pretty good. That puts some deltas like the Mirage III at 20.25" wingspan and the Vampire at 28.5" wingspan. The diminutive wingspan on the F-104 is mighty small at 16.3" but over 40" long.

Maybe keep them between 1/16 and 1/18 scale. This way they are not terribly far apart from each other scalewise and flexible enough for various style airframes. If you can get it into a single sheet of foam more power to you. There is something about not having to get into another piece of material that makes you feel good, whether FFF or MPF.

Also take a look at what these folks are doing http://www.ronknight.com/72056.html
They have some simple rules that we may consider.

Ken
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Old Oct 05, 2012, 01:50 PM
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Horten 229 ??

Was thinking you could go either wing span or fuse length whichever is longer to fit on one sheet
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Old Oct 05, 2012, 01:54 PM
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Originally Posted by dz1sfb View Post

1/16 scale or close to that is looking pretty good. That puts some deltas like the Mirage III at 20.25" wingspan and the Vampire at 28.5" wingspan. The diminutive wingspan on the F-104 is mighty small at 16.3" but over 40" long.

Maybe keep them between 1/16 and 1/18 scale. This way they are not terribly far apart from each other scalewise and flexible enough for various style airframes. If you can get it into a single sheet of foam more power to you. There is something about not having to get into another piece of material that makes you feel good, whether FFF or MPF.

Also take a look at what these folks are doing http://www.ronknight.com/72056.html
They have some simple rules that we may consider.

Ken
The scale 'range' would be a good rule. I think you should take mostly straight winged jets to come up with a 'scale' so you get the 150 +/- SqIn range for many of the conventional jets. Then Mig 15/17's, BAC Lightenings, F-100's, etc, will have shorter wingspans only because they are swept a bunch. Deltas with larger areas are what they are. When major Air Forces clash, there is quite a mix, but they are proportionate!


As far as the Apollo Group, rules similar to theirs would be cool, except they have a narrow 1" wingspan range, a small prop, but nice to have a weight limit (could be higher than their 8 ounce though).. So everyone in their group ends up flying a 'one-of-a-kind' airframe, that is looking like the F-22/F-35. If the rules make it so only a 'one-of-a-kind' ship becomes the only competitive airframe this whole would loose it's appeal. The 'scale range' I like because a battle should have vastly differances in aircraft types, after all NATO forces don't fight NATO forces, right!

Ken, your idea of any type, fitting some rules and guidelines is spot on. Just like the WWII warbirds you do. I'm liking this a lot.

The motor, prop, could be a 'range' similar to your WWII Combat planes so BW, Suppo, TP, and any similar motor would be available, probably limited by watts only, and/or say 4"-7" propeller sizes?

I do like the Apollo Groups scoring ideas, and rank is cool I guess for a group, or just use the term "Ace" at 5 scores, then double, tripple, etc. After all that is the way the Military does it!

If you final a 'scale' size or range (like the 16th-18th range), I will apply this to several jets I like and give one a go. I promise to keep it simple so it can be copied. LOL.......
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Old Oct 05, 2012, 02:14 PM
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Opps.......

Forgot to post a photo. All the talk about elevons, no elevator, etc. What works really well on many jets is to hook up 2 aileron servos, set wing mix to elevon, but hook up an extra control rod to the servo horn, and then connect it to the elevators. Leave elevators split and not linked. Aileron on each side travels in the same direction as the elevator on the same size. Seems like it would be counter acting, but it does work very well. First time I saw it was 7-8 years ago on the Wattage F-86 Sabre EDF, and a MiG 26 (Prop in slot) pusher jet.

If photo is hard to see, I'll take another one if you ask!

Fred

Edit: second photo attached.



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Old Oct 05, 2012, 03:08 PM
Gone Fly'n
planecrazy1969's Avatar
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Quote:
Originally Posted by Freddie B View Post

Opps.......

Forgot to post a photo. All the talk about elevons, no elevator, etc. What works really well on many jets is to hook up 2 aileron servos, set wing mix to elevon, but hook up an extra control rod to the servo horn, and then connect it to the elevators. Leave elevators split and not linked. Aileron on each side travels in the same direction as the elevator on the same size. Seems like it would be counter acting, but it does work very well. First time I saw it was 7-8 years ago on the Wattage F-86 Sabre EDF, and a MiG 26 (Prop in slot) pusher jet.

If photo is hard to see, I'll take another one if you ask!

Fred

Edit: second photo attached.


Thats exactly what I was thinking about doing Fred...that little mod will make these things unbelievably maneuverable...of course it really only works on highly swept wings that you named

Stace
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Old Oct 05, 2012, 03:49 PM
Allways the hard way!
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Like the scale range. Like the motor/prop range with watt range/cap/limit/something to allow hi/low Kv, bigger/smaller prop to suit the specific airframe.

Another limit on motor watt could be battery capacity? Big, hi-watt motor will suck battery dry before the end of the combat session: M.I.A... Combat noob thinking out loud...

George
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Old Oct 05, 2012, 03:49 PM
Slipping the Surly Bonds
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Joined Dec 2006
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Vamp canopy

I am really happy with how the vampire is looking with the VLF fuselage. It is light also. This model fits on a sheet of foam with room to spare. Should perform well.

Ken

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