IMAC Aero Tech 35% Velox Custom Build

[Snoopy1]

Wish I knew someone close that has one. Alas, not many true builders left here in Boise. Pretty much zilch for foam builds. Unless it comes from Hobby King or the like and is BNF, they would look at me as though I'm crazy.
View attachment 100897

Ok let’s get this straight I am no expert. I have built more than ten sets of wings and built three sets just experimenting. But what I can tell you that carving up a styrofoam wing is a lot of work and time consuming for very little gain what I found was on a 40% wing fully cut up only results in about 2 to 3 oz per wing panel gain, plus when you do this you can not vacuum bag the wing. When done you can see the pockets, ask me how I know, if done with a heavy sheet of plywood and weight it works better, but I have never done weight method only the vacuum way. What does show big weight gain is to cut holes into the wing after-it is sheeted. When this done this way it has to be bone very carefully and not ending up with nothing. Be very aware of stress raisers and tress concentration points to get it right. From the little work I have done and played around to reduce weight is not worth all the work and possible wing failure.

 

[stangflyer]

Ok let’s get this straight I am no expert. I have built more than ten sets of wings and built three sets just experimenting. But what I can tell you that carving up a styrofoam wing is a lot of work and time consuming for very little gain what I found was on a 40% wing fully cut up only results in about 2 to 3 oz per wing panel gain, plus when you do this you can not vacuum bag the wing. When done you can see the pockets, ask me how I know, if done with a heavy sheet of plywood and weight it works better, but I have never done weight method only the vacuum way. What does show big weight gain is to cut holes into the wing after-it is sheeted. When this done this way it has to be bone very carefully and not ending up with nothing. Be very aware of stress raisers and tress concentration points to get it right. From the little work I have done and played around to reduce weight is not worth all the work and possible wing failure.

Thanks for all that. I am glad you brought all that up. It just so happens I called my friend Joe Mitchell down in Salt Lake earlier this evening. We chatted a bit and from what I learned, even on his big 54% CAP, he saved about 3 to 4 ounces per wing. Just really not worth the effort on this plane. However, he did mention that "coring" the control surfaces, i.e., ailerons, elevators and rudder does offer some awesome benefits. Not much of a weight savings, however he swears the planes fly much crisper and cleaner especially IMAC designed. So, I will probably core the control surfaces and leave the rest alone. Thanks Snoop!

 

[Snoopy1]

Thanks for all that. I am glad you brought all that up. It just so happens I called my friend Joe Mitchell down in Salt Lake earlier this evening. We chatted a bit and from what I learned, even on his big 54% CAP, he saved about 3 to 4 ounces per wing. Just really not worth the effort on this plane. However, he did mention that "coring" the control surfaces, i.e., ailerons, elevators and rudder does offer some awesome benefits. Not much of a weight savings, however he swears the planes fly much crisper and cleaner especially IMAC designed. So, I will probably core the control surfaces and leave the rest alone. Thanks Snoop!

I sure it does removing weight from a control surface that moves 0.12 sec per 90 degrees will make a big difference. Remember the servos has to accelerate the surface up to speed and slow it down with out over shooting the pre determine position, all within a 1/10 of second. So weight plays a big part in how the surface reacts.

 

[stangflyer]

I sure it does removing weight from a control surface that moves 0.12 sec per 90 degrees will make a big difference. Remember the servos has to accelerate the surface up to speed and slow it down with out over shooting the pre determine position, all within a 1/10 of second. So weight plays a big part in how the surface reacts.

That's what I'm hoping for.

 

[dhal22]

Pattern flyers (builders) motto: you take care of the grams and the ounces will take care of themselves.

 

[49dimes]

Okay gents, it looks like I'm going to have 4 days off during the Christmas break. Which means that I should be able to get a little bit done on this build. I have been mulling around in my head a few ideas before I even get started and thought maybe I would pose the question to a a few of you experienced builders. I know that Terry Wiles and quite a number of other gentlemen do this, however I'm curious as to the real benefit of it. What I am talking about is cutting lightning holes in the flight surfaces such as the wings stabs fin and rudder. I think it looks cool but I'm wondering if the weight savings is negligible enough that it's even really worth doing it. What do you guys think? Kelly, Doug, anyone else that has had experience building foam core planes? Is the weight Savings of cutting lightning holes in the surfaces really worth the extra effort?
View attachment 100896

Yes it is! And the wings too. Except in the wings don't cut holes but cut uniformed sections out to form what looks like ribs. Just be sure to make the middle rib or inner/ outer ribs (Multiple servo wing) wide enough to hold the servo mounts. As they say a penny saved is a penny earned. The Godfrey plans I had showed doing the wing this way to save approx. 5oz per wing panel (50cc plane). The ailerons, elevator and rudder showed hole bores. As did the fuse sides. I don't know what the actual weight savings was but my plane was 18.5 pounds. The planes built from older plans that did not have this process were coming out over 20 pounds for a 82" span Model.

 

[Snoopy1]

Yes it is! And the wings too. Except in the wings don't cut holes but cut uniformed sections out to form what looks like ribs. Just be sure to make the middle rib or inner/ outer ribs (Multiple servo wing) wide enough to hold the servo mounts. As they say a penny saved is a penny earned. The Godfrey plans I had showed doing the wing this way to save approx. 5oz per wing panel (50cc plane). The ailerons, elevator and rudder showed hole bores. As did the fuse sides. I don't know what the actual weight savings was but my plane was 18.5 pounds. The planes built from older plans that did not have this process were coming out over 20 pounds for a 82" span Model.

Will agree with you that on the older planes it has more of an effect but to day with foam at around and less than 3/4 pound per cubic foot there is not much to be had. Most of the weight is in the glue and the wood.

 

[49dimes]

Will agree with you that on the older planes it has more of an effect but to day with foam at around and less than 3/4 pound per cubic foot there is not much to be had. Most of the weight is in the glue and the wood.

I guess I told on myself how long I have been pulling planes from boxes .

 

[stangflyer]

Yes it is! And the wings too. Except in the wings don't cut holes but cut uniformed sections out to form what looks like ribs. Just be sure to make the middle rib or inner/ outer ribs (Multiple servo wing) wide enough to hold the servo mounts. As they say a penny saved is a penny earned. The Godfrey plans I had showed doing the wing this way to save approx. 5oz per wing panel (50cc plane). The ailerons, elevator and rudder showed hole bores. As did the fuse sides. I don't know what the actual weight savings was but my plane was 18.5 pounds. The planes built from older plans that did not have this process were coming out over 20 pounds for a 82" span Model.

1.5 pounds on a 50-60cc airframe is a lot. But I don't see any way possible to remove that much weight from this 35%'er. Then again, what do I know? I have never "cored" a foam plane before. Joe tells me he saved about 3-4 ounces per wing and about half that per each stab half and fin/rudder. That would make a total of around a pound for the entire 50% CAP airframe.



For the sake of simplicity and time factor, I will probably only core the ailerons, elevators and rudder. At that point, I will weigh the removed waste and if it is substantial enough, I can always go back and core more if I want.

Since it is "STILL" snowing here and I have all the presents wrapped for my Kids/grandkids.... I am going to start attacking the Velox build tomorrow after spending time with my family.

Wishing each and every one of you the happiest and merriest of Christmas's. I hope you all get exactly what you are hoping for. I wish for everyone...peace and love and joy and prosperity for the upcoming new year. Lets keep 'em flying.....

 

[Forgues-Research]

1.5 pounds on a 50-60cc airframe is a lot. But I don't see any way possible to remove that much weight from this 35%'er. Then again, what do I know? I have never "cored" a foam plane before. Joe tells me he saved about 3-4 ounces per wing and about half that per each stab half and fin/rudder. That would make a total of around a pound for the entire 50% CAP airframe.

View attachment 100935

For the sake of simplicity and time factor, I will probably only core the ailerons, elevators and rudder. At that point, I will weigh the removed waste and if it is substantial enough, I can always go back and core more if I want.

Since it is "STILL" snowing here and I have all the presents wrapped for my Kids/grandkids.... I am going to start attacking the Velox build tomorrow after spending time with my family.

Wishing each and every one of you the happiest and merriest of Christmas's. I hope you all get exactly what you are hoping for. I wish for everyone...peace and love and joy and prosperity for the upcoming new year. Lets keep 'em flying.....

Have you ever considered, a jig built wing using foam ribs, meaning you assemble all identical rectangular rib cores, , hmmm hard to explain, I will get you a link of one of my laser built thread