Quote from: roopeshkrishna on May 28, 2012, 11:13:52 PM
keep ratio as 5:3:1.5:1... means.. if wingspan is 50 inches, fuse length is 30 inches at least, and 15 inches for tail plane and 10 inches for rudder..

As Rupesh Sir has stated, shall we all stick with a 50" wingspan? Need everyone's opinion on it.
Next...Sumeet has put up an excellent set of requirements. So shall we all stick with that? Need everyone's opinion on it.
I would like to add some more points under requirements:
1. Takeoff Distance
2. Landing Distance
3. Range
4. Ceiling
5. Rate of Climb
6. Stalling Speed
7. Maximum Speed
Now I think we should also decide on the above 7 points.
Please start suggesting....

Guys one important point: lets first fix a set of "UNITS"
Distance : inches? or mm? inches could be a winner since the dimensions are large in aero field.
Weight   : Kg? since we are used to it everyday.
Time      : seconds? same as above
Shall we follow the above units? please suggest if any other form is used frequently. lets have a united opinion on it & fix it.

I would suggest we all keep noting important points, from discussion in this forum/topic, in our notebooks, so that even if our comp is off we can still keep working on our wonderful project....wont keep it idle...not at all...

and we must need the grace, blessings and advices from Seniors.. all Respected Seniors.. please advice and guide us in this project, to fulfill our dream.. the dream of RCI.. 

50" wingspan is just fine.

Now lets discuss on points you mentioned......

"Landing and Takeoff distance"...
As we all know that we always have a problem of a good large Airfield. Most of us are bound to fly in local small playgrounds with lots of activities already going on there. So, A good fix is to keep Takeoff and Landing distance smaller as possible. But on the other hand, It will require the plane to be lighter in weight or should have flaps or spoilers or combination of both.
My opinion is the "distance no more than 20 feet" for both Landing and Takeoff.

"Range"...
I still don't get your idea with the "Range". Is it Radio operation range(Things get pretty unpractical here as the effectiveness of radio is completely a different thing). Or it is the maximum distance the plane can travel at full charge.

I am pretty sure that you meant the second one, The Distance it can fly to...Right?
So, is our plane is going to be specialized in any operation like wild-life tracking or something like that?
before having such goal....I don't think that discussing on the "range" makes sense. After all we are going to fly it as a usual R/C plane, Standing at some place comfortable and flying in loops over and over again. Unless we intend to get our plane to fly pass the certain distance, The "Range" doesn't need discussion. What you and others say?

"Ceiling"....
With respect to aircraft, a ceiling is the maximum density altitude an aircraft can reach under a set of conditions. Copied from Wiki...can read further....
In R/C planes, Ceiling clearly depends upon Radio range + how far above we can clearly judge the orientation of our plane. So, what must be discussed here....?

"Rate of Climb"...
This is a good aspect to determine the ability of an aircraft. Greater rate of climb means faster it is to reach a certain altitude. Need seniors here who have a good R/C flying experience. They can suggest it more precisely as they have flown different aircrafts and can tell the difference between flights.

"Stalling Speed"...
Lets set it to around 20kph...or 4kph more or less? To experience how fast it is....Just drive a two wheeler on that speed and imagine an R/C plane taking off at the same time......I have done it.  

"Maximum Speed"...
As we want to keep plane easy to fly for the beginners but also desirable one for the intermediate or advanced guys. It must have wide speed range. What about 70kph (~43mph) at max....? Is it that good?

Now lets see what others say about it....

Thanks.

nice discussion..

I agree with your opinion on Range & Ceiling.

20 feet is a good takeoff & landing distance

need guidance on Rate of Climb, Stalling Speed and Max. Speed from Seniors

One more suggestion from me...

Why don't we set expected payload for our aircraft...
I am suggesting this because we intend this aircraft to be built by beginners. So there are chances that sometimes the plane will end up more heavier than expected.....Thus, Setting a payload will give an idea of "with what maximum weight this plane could fly". I am referring this as payload because if the plane's AUW is weighing nearly equal to Expected AUW, Then we can think to carry an extra load on the plane(Paratroopers, Dummy Bombs, tiny Bag of floor to mimic explosion once it is dropped, paper cuttings etc). I hope you have the idea now....

For example: Lets suppose the plane's expected AUW is around 0.75KG. while the actual ends up at 0.825KG. It is not a big deal for an advanced or intermediate guy to manage. But for beginners, It will definitely make him think that would this plane fly or not....Even I have asked such questions regarding the increased AUW from others while I too have been asked it many times. So, Lets fix a "Maximum possible AUW" (lets not call it payload as it can cause confusions further).

Another problem here is that we don't know the expected AUW of our plane till now, So, we can go with the formula:

Maximum Possible AUW = MPAUW = P X Expected AUW
(Where P is greater than 1)                              ===>(1)

Now we just have to fix the number P and that's all.

We can also derive P on the basis of maximum static thrust.

P = Maximum Static Thrust/Expected AUW          ===>(2)

By putting the value of P from Eq.2 to Eq.1,

We have,

MPAUW = Maximum Static Thrust

Or in other words, MPAUW must be less than or equal to Maximum Static Thrust to achieve required performance.

Further,

Actual AUW <= MPAUW
It is the condition which needs to be satisfied to fly the plane without any risk...

However the plane can fly even if the condition doesn't satisfies but then it will result in increased stall speed and will require longer runway for takeoff and landing.

Payload can be easily calculated now,

Payload = MPAUW - Actual AUW
It gives the extra weight that can be carried in the flight.

I request to other members to give opinions......This thread is getting more interesting now...

Thanks.

great considerations..

hi,

sumeet whatsoever said, are we planning for some kinda competition or designing a UAV.

lot of factors are to be considered during the design process. a number of problems have to be tackled and solved. all this requires patience, time and lots of money.

have been all thru this and now currently into experimental designs like using solar cells and a autogyro.

lots of trainers have been designed and are available, ultimately its the odd aircraft that stands out.

Sandeepji, please share possible tips from your years of experience here once.. as it will be great helpful to all..

Absolutely Sandeep sir...It must stand out....and yes....Money and Time are the primary investments in this project. If mentors like you are with us, We don't fear anything. We will definitely succeed.

Well, Lots of trainer aircrafts are already being sold, Build and flown everyday and most of them have satisfied owners. The main thing we should consider is what odd we can do and what we expect with this project. Without knowing our own expectations, we can't design a perfect plane that everybody can enjoy flying. Everybody face some problems when they just start in this hobby. We all learn with our good and bad experiences and that's the key thing. By minimizing commonly experienced problems in model aviation should be the direction that our project should proceed in. So more & more people can fly without problems. If I can play a part in it, then it is an opportunity for me.

Well I know its not a competition. And fixing those numbers like I did was kind of unfair  . But as far as we are on the stage of discussions. We all have right to make suggestions and give opinions. And I just did mine. I don't want to force somebody to follow my opinions. Even I would rather be happy if somebody cuts my suggestion and suggests something else. That way we would have more things to discuss. We definitely need more and more involvement and discussion here.

And yes, Please share your experiences with us as it will be so helpful and interesting as well.

Thanks.
Cheers.

What I think is that we are not planning to build an outstanding plane. neither is our objective to sell this plane....or to place it in competition. let this be very clear that we only want to make our basic knowledge very strong. hence we should start with a simple plane...a trainer.....which will cover basic practices....which a novice can also make. thats all our objective is. we need to get to the core of understanding the basic aspects of aircraft design....like aerodynamics, power, stabillity & control, structures, etc. The knowledge thus acquired through covering these design aspects has to be simple in understanding for a beginner. Thats all my objective was. People come here to get this knowledge, but its scattered. What I wanted was a single project which will cover all the basic design process to be in one place. so that a novice can understand step by step what goes on in this beautiful journey...called aircraft design.

Sumeet you havent fixed any numbers...in fact you have shed light on normal practices, which is great!! we all over here need to know what are the basic thumb rules so that we can relate them and combine them with our basic knowledge and generate a real life practical, useful and easy design.
Sumeet you have given really useful details....I appreciate that a lot.

About gross weight.
To keep in mind - should take min. takeoff & landing distance, max. speed, can be hand chucked (though its not advisable for begineers), easy to carry....from home to ground.
So a value of about 800gms max should be thought of.
What are other's opinion?

Thanks Vikalp Ji.
800 grams is fine.

buddy i m no ji...just 26 yaar.
ur welcome

But I am not 26 naa.....I am 22. 

800 is fine, but we should show a breakup of this 800.....i.e what all is included in it.
say electronics weight
1. Atleast 3 9gm servos = 9gm x 3 = 18gm +10 gm for push rod = 28~30gm
2. Motor (brushless outrunner) + prop (plastic/wood) =  150gm + 15gm = 165~170gm
3. Motor mount = 100gm
4. ESC = 35gm
5. Battery = 175 gm
6. Structural weight = 300gm
Total = 810gm
Well this is just an approximate figure, I may be wrong somewhere. I doubt about the structural weight. About the weight of electronics....I got it from sellers website & considered at a higher end.
Need other's opinion too.
My objective here is to know the thumb rule, but to also think about the logic that went into fixing this thumb rule.

Quote from: vikalp11 on May 30, 2012, 11:35:38 PM
2. Motor (brushless outrunner) + prop (plastic/wood) =  150gm + 15gm = 165~170gm
3. Motor mount = 100gm

Vikalp we can cut down a little weight from motor. as Motors like Cf2822 has wt less than 50gm and thrust of nearly 750 gm. for more thrust we can go for turnigy motor with wt of around 80gm and thrust of 1000gm.
Motor mount wt weight can also be reduced by 40 gm.
In total 80 to 100 gms can be reduced from electronics. which can be adjusted to make the frame more tough by reinforcement.

Agree with Swizera. 

Nice initiative friends...!! 
Would be really helpful for beginners like me..