remcl1

My Feedback: (3)

That may be true. I did not say he lacked knowledge. I said he was Rude. In fact I am sure he has a considerable amount of knowledge and that is why he has a hard time in just answering a simple question. I am sure to him there are no simple questions. He has to look at it from several angles and when everything does not fit just right you clear the slate and start over. Anyway, I am sure he means well.

simmo8

lol!! yea why not have some fun with it. would it be posible for a video of the plane flying after you put in the bigger tank if not no probs

thanks anyway

simmo8

i think i am replying to the rong people lol oh well Im new to the site

remcl1

My Feedback: (3)

I volunteer to take video. If I can keep up with it.

simmo8

thanks alot lol

Zman39

My Feedback: (6)

Your the true plane designer and the scorpian is impressive. But yes, I had to have fun with naming it with you in mind

Mike Connor

My Feedback: (5)

All I need is the sound to do a Doppler. I hope I will prove the gps right, not wrong.

soarrich

My Feedback: (98)

Tell us a little about your GPS unit.

Zman39

My Feedback: (6)

Easier to link than to tell . Here is a link to it on Garmin's site. Nice thing about it is its size and weight.

https://buy.garmin.com/shop/shop.do?cID=144&pID=220

remcl1

My Feedback: (3)

Tell me about how this dopppler works and why is it more accurate getting its data from a video than an on board GPS?

MJD

My Feedback: (1)

Everyone here seems to think there is a vast amount of rudeness in the post by rudeboy. I don't see it. He may have a direct way of stating things, but ALL he has done here is to list the things he would do if starting off on a similar project. As such, you can take the positives from this or you can take offense. The way you interpret it is strictly up to you...

Airfoils - what he says is quite true, an accurate job of reproducing a low drag laminar flow airfoil really cannot be done by hand, but one can certainly do one's best to get close with whatever techniques you have at hand. To take real advantage of low Reynold's number low drag airfoils, you need very accurate reproductions, generally involving CNC cut female molds and good composite construction techniques - not everyone's idea of a quick home workshop project. But you originally said you had a laminar flow airfoil, and he simply resopnded by saying you can't build one by hand. You were mistaken in your terminology, he responded correctly based on your terminology - relax. Highplains pointed out that by avoiding valley, flats, edges etc. you can improve the tendency to keep flow attached - also quite true, but I have my doubts that one can achieve full laminar flow. IMHO the jury's out on that one.

Wing - thinner airfoils favor high straightline speeds. Heck, you could build a second wing and shim the wing saddles to fit without rebuilding the entire airplane, if you chose to do so. It could even have internal aileron linkages. You could compare the benefits.

Rounded fuselages - yes they reduce drag. A slap-together fuselage could incorporate more rounding with fairly simple construction techniques.

You can indeed reduce engine drag by cowling or rear exhaust with or without cowling to reduce frontal area. It is feasible you could fit a rear exhaust engine to an existing design, with or without cowl. Maybe you have one, maybe you don't.

Airfoil the tail. True - many people neglect decent attempts at tail surface streamlining. Not all, but many.

Internal linkages. Not hard to do, good idea. Hard to do on an existing model, yes. But not hard when starting from scratch.

Landing gear - yup, simple and practical. Remove landing gear and hand launch. This is something you could do with your existing aircraft and as you were looking for in the first place, you would indeed squeeze a few more mph from it.

Using a Q500 muffler - correct advice there, and something you could do with no structural changes. And yes clipped pylon props often work out well if you have sufficiently small frontal area to take advantage of them. This too, is practical advice you could try out.


Part of the European style of response on this forum, if I can grossly generalize based on observations, is that there appears to be a lot more effort by modellers over there to build dedicated speed models - true "extreme speed" models - using many of these known techniques for drag reduction. And again to generalize, many of the European crowd seem to be puzzled at the term "extreme speed" used freely on this side of the pond when referring to either prop jet ARF's, or quickies with .50's, or sport models with monster engines, or whatever. It all depends how fanatical you want to be. I guess they don't view "sport speed" as "extreme speed".

So.. you have a choice of taking or leaving his comments. You could look at them and decide to yourself that you may make another one down the road, and see how many of those ideas could be incorporated in whole or part in a simple sheet balsa/foam sport speed aircraft. Might be an interesting and rewarding project. Or you could simply choose to respond with "thanks, but I don't plan on making all those changes, but might see what I can do with some of the ideas".

My point is, instead of people pissing on RB because he posted a list of known drag reduction techniques some of which would require redesign/reconstruction of the current design, but many of which could easily be incorporated into even a simple model from the outset, maybe just read it and take the positives from it and say thanks. I don't see how he had the intention of insulting anyone. It may be that he stated some obvious design issues, but so what? It's your choice whether you take insult at that or not. The point of forums is to learn and share, and he has all the right in the world to offer his ideas on the subject.

That's my $0.02.

MJD

Zman39

My Feedback: (6)

Original first post by me was asking; here is what I made, anyone got any ideas on how to get a few more mph's out of it. RB's response was to "summarize" change the wing and change the fuse. That would have been a good response if my question was "here is what I made, didnt work, need to start over, any ideas? Insulted? no way, just a post that didnt address my question at hand.


But, at this point, none of it matters, I achieved my goal and am satisfied.


Z

Oh and I agreed about 15 post or so ago to not call it a laminar airfoil anymore. It's official name is BS airfoil which means don't have a clue what the airfoil is but worked fairly well.

Mike Connor

My Feedback: (5)

It may not be any more accurate then a GPS but it is one more simple way to help verify what the GPS is saying. Confirming a speed by as many methods as possible gives more validity to the claim. Most speed measuring methods are not perfect but if you get two or more in the same ballpark the credibility does go up.

It is a program that measures Doppler effect from a sound file to determine speed. Here is a link to the program if you care to read (translate from German) or download and play with it.
http://www.sprut.de/electronic/soft/scope.htm

MJD

My Feedback: (1)

Yeah I know, I wasn't belaboring that point, not intentionally at least.

Anyhow, that makes it either a Staedlter-Mars or a Bata airfoil, depending on whether you used a french curve or a shoe for the profile.

One day I'll get around to finishing up rev. 1 of a sport speed design using normal/fast/simple construction. Me and a few others I reckon. It's "on the list"..

MJD

Zman39

My Feedback: (6)

soarrich

My Feedback: (98)

Thanks, I just bought one for $30.27 off pricegrabber.com

I have a few planes I'd like to try it in for speed, but I fly in a park with boundries and I'd like to see if I am staying within bounds.

Zman39

My Feedback: (6)

That is a great deal! You will like it Rich, nice little unit.


Z

Rudeboy

10-4... Rudeboy out!

rmenke

My Feedback: (13)

Zman 39:

Love the way your mind works, keep it up. Also learn to listen to CP, a great source of good information among many. Based on 6 years experience racing a 40" Q-500 wing, thats all it takes to turn and land well. Also did a 40" wing with Jett 60LX, darned fast, flew well, and landed just fine thank you. If your jett 50 is not the LX model, your not going to get much more out of her. The Jett Q-500 black pipe will give you a few more rpm's but not a bunch. Your general design basically follows my time proven "Yellow Jacket" design, which is basically what you have except the nose extended and widened for a 10oz tank and the rerar end extended to offset the nose weight. If you gotta add weight to CG, your just to lazy. Right now, you are into a speed zone where streemlinning is required within reason. What you have is fine except for the nose. You can add some balsa up front or use other cowel approach and find around 8-10 MPH IMHO. A bad switch killed my first YJ design with a 40" wing. Had enough flight time to find that that is enough wing, period, and no did not skid in the turns. When building new #2, had a composit 52" wing laying around that I ended up using. With the Jett 60 LX power, you can start her, needle, set it down and taxi out and take off like any other sport airframe. You can keep the speed down to get used to the thing. So far, none of the local all out Q-500's or formulas have outrun her WFO. It will happen eventually I am sure, cause there is alwlays someone bigger, stronger, faster, in the intrum I fly around with a big grin on my face at less than 1/2 throttle. Unfortunately, there is seldom a challanger. Oh yea, it will hover, try that with your Quickees guys. Will try to attach a couple of picks, ENJOY