Hi,


Want to know has anyone put two engines in the Eurofighter scale?



Cheers

Break the silence...


Well, I contacted Fiber Classics. They said putting the two engines in the Eurofighter will be fine. Just reinforcing the entire airframe with T6 carbon fiber is a good idea. I also put aluminum gear mounts on top of the carbon fiber reinforced ones. I am in the process of fusing the wings to the fueslage so that the energy from the wings transfers to the fuselage and to the nose and tail giving the aircraft a shifting CG and balance.


Next is to work on adding 450oz of fuel.

BTW, before anyone else makes a silly coment, please read about Reynolds Numbers for RC aircraft, Structural Engineering and Design Techniques, Physics 101 (Mechanics) or even better classical mechanics! (Hamiltonians), Fluid Dynamics, Gaussian Distribution, Dynamical Systems, and Linear Algebra 101.

After I get the air frame together, I plan to do wind tunnel tests to see how she holds out. According to the figures (you can find out for yourselves), with a delta wing the CG is negligible. However to distribute the weight evenly along the fuselage I moved the engines back 8 inches from the original engine mount positions.

next post in a couple of weeks...


Cheers

Did that and more thanks. Nice way to encourage discussion, BTW.

Now that I'm qualified to reply, this makes no sense:

-Maybe you could explain what you mean. The loads are transferred to the fuselage by the spars as supplied with the kit. If you are actually going to make the wings non-removeable, You could add strength by running CF across the wing joints. Don't know that you need it - in which case it's wasted effort. None of which affects how the aircraft handles CG location. The CG postion is not negligible. As with any other plane, the is a range of acceptible locations. I suggest reading "Aircraft Stability and Control" by Perkins & Hage.

And now for my silly comment:

Englebert Humperdink is my hero!

LOL ! Todd - even though that image was pretty funny, you didn't seriously think we could leave it up there did you ?

Thanks for the laugh, and for checking to see if the mod's were awake.

Gordon

Sorry Gordon,
Couldnt resist

Actually, I think he needs a set of wings like these....

Arrgg - I guess I didn't see the image thru the flames. Todd- send it to me.

Hey Todd , were you going to Ocala on Saturday or Sunday?

John,
Plans are for Sunday, weather permitting. Can you make it? ....

Sending you an email now

Todd

what I mean is with the wings attached permanently to the fuselage (hence the term fused) the wing load will be transfered from the wings to the fuselage instead of just the spars. I increased the weight by 18lbs and the airframe is designed for less if set up the original way it is designed.

since I plan to put high G loads on it with a heaviar airframe, it is the only way to do it.


btw if you read all of that then maybe you would have understood and I wouldn't have to 'water it down'. :stupid:



Cheers


Cyril

OK!

Down Boy, DOWN!

Todd, I PM'ed you.

No but a huge trailer will do nicely.

This is part of my Ph.D. thesis;

"A Fiber Optic Precision Flight Control System".


I am not that into the hobby. I'm just kinda passing along things I learn by applying my knowledge to this hobby. I am not an aerospace engineer, but I have had fluid dynamics, hydro dynamics, and thermal dynamics. The same things that aerospace engineers study. I was more of a theorist. I did my first Masters in Moscow State University faculty of Mathematics. My second MSc in University of Tokyo Computer Science department (Artificial Intelligence), My third MSc in Theoretical biochemistry In Stockholm. Guess you can say I get around!

Before I started this project, I was doing protein folding, then autonomous robotic control with varying degrees of freedom.

Enough shock for one day...see you all later.

Wolff,

May I add a comment here? This is not meant as an insult, but rather a constructive criticism.

You are posing questions to this forum with an obvious attempt to glean knowledge from those of us who "are" involved with this facet of the hobby. You will find that many of the fine people whom frequent this area of RCU "are" Aero Engineers, UAV professionals, Aerospace professionals and/or have a deeply embedded knowledge of aircraft design, flight or aviation experience. Everyone who has responded, thus-far, is highly involved with miniature turbojet operations and their associated airframes and equipment. Furthermore, two of the individuals who have responded to this thread are Aero Engineers. Yet, instead of considering the input of the participants of this thread, you've infused condescending comment and appear to choose to ignore the advice given - Which is entirely your option.

I can assure you, you won't find a friendlier, broader knowledge-base of miniature turbojet operations anywhere. The information and willingness to help, from the folks within the Jets Forum, is unsurpassed. Unfortunately, your questions, followed with caustic and somewhat belittling remark, will likely get you non-productive or negative responses.

By your own admission and as evidenced by other threads, your experience with turbines and jets, in-general, is nil. My suggestion would be to ask questions, learn and participate without looking-down on anyone. You may be in for a large shock yourself if you were privy the education level and current career status of the folks trying to help you out.

Again, I apologize in advance if this somehow offends you. It was not meant as derogatory. It was an attempt to help you get the information you desire. I wish you only success in your venture and look forward to helping you wherever I can.

Warmest Regards,

Craig

Craig,
You took the words right out of my mouth. Wolffman, take a look at the "Anyone working on a Harrier" thread and "High Bypass Turbofan Engine" thread to get an indication of the high level of technical expertise that prevails in this forum.

Wolffman, out of curiosity - what sized engines would you be looking at for a twin application in the Eurofighter, and why twin vs. single for what you are doing? Giving a bit more info like this may help people provide you with a useful recommendation.

Didn't need watering down, you just need to learn how to communicate. Maybe now you could "water-down" the reasons that CG location is "negligible" - whatever that means.

Since you have made it clear that you are indeed superior to the rest of us, please print the analysis that leads you to the conclusion that you need to strengthen these wings. How far past the ulitimate load would the extra 18 lbs take the spars? Please, please, please let us all learn from you, great one!

Ok....I rescind my comments

Have a wonderful day! :sunsmiley

Todd

Cyril,

Did you decide to go with the Eurofighter instead of the A-10?

Oh,...and listen to the advice here on RCU as there are a bunch who have MUCH more experiance with your endevor than you and I. They really ARE a nice bunch.....most of the time ;>)

Okay guys - I realise that some of Wolffman's posts could be read as condescending, but let's try & be nice. Because the "cues" that you would get in a face-to-face conversation are not there in written communications - well, sometimes what the author means and what the readers see can differ. Maybe, just maybe, that's what happened here.

So, before we get the tar & feathers out , maybe we could show that we are a nice bunch of guys (yeah right !!) by saying to Wolffman - how about starting this whole conversation over again in a way that won't seem condescending...

Regs,
Gordon

Hey wolfman can you post a picture of your Eurofighter. I want to
see you modification to the wing.

: )

OK, I can knock off my cynicism. I was working on a list of "Stupid things I've seen PhD's do", but I'll save it for another time.

However, there is no way to interpret a review of one's resume through books-read and degrees-earned as anything other than a pointless, rude, and self important exercise. (If he had done that face to face, the results would have been worse, not better:devious: ) That gives the rest of us the impression of someone who already "knows-it-all". Why would anyone attempt to help someone like that? If Wolffman can knock it off, we can move on.

I have now taken a look thru Wolffman's other posts about this plane and project - and it does not look like a way to run a sucessfull project. However, I will not get into specifics unless he indicates that he actually wants the advice.

Ok I get it...the good ol' bo network. I thought this was between me Todd and the other guy who insulted me. I didn't expect people I don't know to attack me as well. How veracious can you be. Well this will be my last post in the forum.


Goodbye

Wolfy, you can't just show up, post a question, tell everyone that you don't want to hear anything from anybody with less than a degree from MIT and not expect some backlash (I know you didn't say exactly that....but that's what everyone read). There is an unbelievable amount of knowledge and experience here, you just have to know how to tap into it. Not insulting people up front will go a long way toward that. Stick around....everyone might learn something.



BTW, veracious means honest........



Bob

Wolffman,

I don't think there is any "gang banging" going on here. Just a few that doubt the veracity of your statements.

Please stick around and make us believers. I for one would like to know your logic on what effect a blended wing will have on the placement of the CG location. How can a blended wing possibly shift the CG???

Unfortunately this guy seems to be digging for info. in this forum and not willing to share anything he may come up with. Perhaps he is being protective of his "phd thesis" or perhaps he has a chip on his shoulder. Who knows.

Too bad. EFIS is a fascinating area about which I would like to learn more.

Antony

All right then....


We can go through this step by step. I am of course not going to share everything, but some things I am willing to share.

Right now I am in the process of reinforcing the fuselage with carbon fiber. My first attempt was unsuccessful cause of my lack of understanding about epoxy resins and how to use them properly.

I am on my second attempt and things are working out nicely. I used Wes system epoxy and put a little fiber glass powder in there to make it tough and a little more elastic.

In reference to the shifting CG. I then put four 120oz fuel tanks (the eurofighter scale oval shapped tanks) right by the engines toward the cockpit in the center. I used epoxy to hold them in there. the fuel flow starts in the front tank then ends in the rear.

I moved the engines back 8 inches to fit the fuel tanks in there.

This should give me about 30 minutes of flight.

Looking at the figures;

~5.6 lbs for the engines
~2.8lbs for the tailpipes
~26.25lbs of fuel
~7lbs for the avionics
~9lbs for the airframe reinforced with Carbon Fiber

Total new weight 'wet' will be ~50.7lbs.

This undoubtedly will increase the take off and landing speeds. But it still is not even close to the real wieght of the eurofighter when doing a scale comparison, but the flight envelope should be close. +- 5% difference.

I'm using Solid Works to help with putting all the components in and calculations.

If you think this is heavy, you should see my buddies UAV down at JPL. It wieghs over 120 lbs and is 120 inches long. I think they shrunk an elephant and put it in the UAV!

So this is how I redesigned the europfighter. I think it is stronger and will fly better.

I have access to a wind tunnel, so I will test it in there and get some critical data such as take of and landing speeds, stall speed, and others.


my next post below it about the EFIS....