The Ultimate Test......

[all_fly_all_day]

Hello everyone,

Starting tomorrow hopefully, I plan on putting this forum to the untimate test. I myself have slowed in this hobby a bit lately, due to lack of money and keeping grades up at school. But one of my friends, the only one into RC, has picked up on the hobby and has been fooling around with it for awhile now. he currently owns a Pico Stick-F, which he is taking very slow. Before the Pico he had a TM but he is pretty impacient and he didnt take the time to build it right, and to learn how to fly it properly. We decided we would build some type of plane over the winter season. Today he bought a Guillows Sky Hawk kit. He has very little experience in building kits the right way. but he has built them before. I told him in the nicest way possable to wait before he starts building it. And that i could get help from all you experts out there. Heres what i know about the kit so far. it is a Gillows laser cut Cessna Skyhawk U control plane, but he said it gives directions on converting it to gas and electric. 36 in. wingspan. The equipment we hope to use in it...2 GWS pico servos, GWS 4RP reciever, GWS power plant, GWS ESC. The kit included tissue to cover it. But i know well enough not to use that stuff. He also bought some extra balsa in case he needed it. I told him we would prolly use it to replace any heavy, or weak wood. that might be in the kit. I watch and read these forums often so gather as much information as i can on the hobby. And i have learned much. But i lack the "hands on" skill. I have build models before. I know basicly how to do it. So here is the test my fellow RC modelists, over the next week or so I will be asking questions on basicly whatever im not sure about during the process of the building. And im hoping in the end...I will be able to display a picture of a plane you all helped build. I know some might think that making mistakes is how you learn, and learning comes from experience, but I am hoping that you will all share your experience with me, and my friend, so that our "expirience" doesnt turn out in disaster. And that you will all be able to view how you contributed to this plane. And for now, any advice you might have please share, anything that can come to mind. I will be very greatful for.

Thanks to all,

Brandon

[miraclesailor]

Brandon:

I really appreciate that you are trying so diligently to understand this hobby and I applaud you future efforts. Since you are not building from a known quantity (electric kit), you are kind of venturing into “no man’s” land. What I mean to say is that there is no hard and fast rule to what you are putting into the plane for radio equipment and powerplant. Hope the plans have some idea. If you know the wing area, the weight of the plane, and the type of flying that you are trying to accomplish (Trainer, acrobatic, scale, etc.) you can come pretty close to what to use by looking at reviews of planes that are similar flyers and copy them. For example if the plane is a 36 inch wingspan, weighs in about 11 to 12 oz and it is a non-acrobatic type of plane then you are looking in the 280 motor range using 6 to 8 cell 300 MaH NiMh batteries. You will have to weigh all the things that you want in the plane and add to the total of the weight.

Another thing is, you are making a balsa built plane. There will be mishaps and you will be repairing the plane. Balsa repairs nicely but looks ugly after a bad smash up and before the repair. Take heart most of the pieces will go together like a jigsaw puzzle and with some patience you will not even know there was damage. The only kind of plane that I know that bounces is made of EPP foam, but that is heavy. I like repairing balsa over the white foam EPS (not as durable as EPP) for final looks. But it may that a little more time. In the end it will always, IMHO, look better.

Another thing to think of is truly building from scratch. For example look at the RCMicroflight site and see if there is a plane that you can build easily and has all the information on power and radio. One of the free ones, on the site, is the Starlite (http://www.rcmicroflight.com/plans/starlite/index.asp). It is a basic build, light and easy to fly. This will only cost you the price of the balsa to make and then figure out the radio equipment to put in it.

Hope this helps,
Dan

[all_fly_all_day]

Thanks Dan for suggestions. It helped with some of the basic quiestions i had. Well, i went to his house today to start the building. We have the fusalage (sp) almost completely done, except i thought it would be a good idea to leave two places unfinished fro now. The first place was right behind the cowel firewall on the bottom of the plane, in case we needed to get access when installing the motor, and the second was the most obvious spot, the top of the cabin area to install the radio equipment. We also finished the tail surfaces. And the plane has about 190 sq. in of wingarea. But now comes the big questions. What is the best way to connect the wing servo to the airilons*? the servo will go in the center of the wing and the surfaces are on the tips of the wing. And what would be the best ocvering to use? Im looking for a inexpensive, strong, easy to apply material. Thanks again for all your help. This plane is looking good already.

Brandon

[Dr Kiwi]

Brandon - good luck with it - we all applaud your efforts to build a "real" plane instead of the RTF route! [Sorry, my bias again shows through!]. For aileron connections you could try DuBro 's Micro Aileron system [part# 850]. For covering you can do no better than use Solarfilm [a.k.a. Nelson Lite film] available through Balsa Products (and Aeromicro too, I think) - it weighs only 20g/sq.m, it irons on easily and is about as srong as you can expect from such a light-weight material (actually, I found it weighs exactly the same as doped tissue!). Looking at your wing area (190 sq.in.) you are going to have to be very careful with weight - even at 10oz you are looking at a wing-loading of 7.58 oz/sq.ft - and, for a trainer, that's really a bit more than it should be. For 36in span a slow flying trainer should probably have a 6-7in chord and thus about 215-250sq. in wing area. At 10oz a GWS IPS S1 or A may just have enough power - any more weight and I feel you might have to move up to a GWS IPS-Dual motor. Dan's suggestion of a Speed 280 motor is a good one, but if you head down that path you might as well fit a Speed 300 with twice the power for the same weight - and with either of these motors you are going to have to live with an even higher wing loading. It is a vicious cycle! Cheers, Phil

[all_fly_all_day]

Thanks Phill, i will look into all of the above:D . THe wing chord was bout 6 in. at its greatest, and about 4 in. at the tips. If you are familiar with the skyhawk in anyway (FMS:cool: ) you know the basic shape of the wings. Though the measurements were pretty crude, I think i am pretty close to the right about of wing area. It surprised me too. It is nice to know that we still might be able to use a battery pack that we have already, since money is coming in slow(winter:mad: ). The 8.4v 300mah NIMH pack is what i was thinking of getting since it seems to be pretty nice. But we have the equivelent of the pack as NiCad (150mah). But im still not sure about anything. Trying to take it as slow as possible. The next step is the covering. And the Skyhawk isnt excatly a "box". Even the tail surfaces are built with a "wing form" to them. So this will problably be the slowest part of the job. we have a couple other desisions to make also before we start covering. Which, as of now, i have no clue on what to do. The fusalage is built as "formers and stringers" so im trying to figure out the best way to install the battery and radio equipment. I had the basic idea of permantly installing the battery and putting all electronics on a balsa "board" over the pack. But the inside of the body is curved and has no solid surface except the covering after its on. A real problem, but with a problem, theres a solution. Ahhh so many things to do. Well, thanks again for all the insight. We are hoping to make this one a real keeper.

Keep on flyin~~~

Brandon

[Dr Kiwi]

Brandon - A permanently fixed battery is not a good idea - you might have to then fit a charge receptacle and on/off switch, adding to the dreaded weight!. Is there some way you could fit a horizontal balsa platform between two formers, midway up the fuselage sides? [Fore/Aft position determined by the CG]. Velcro your receiver and ESC on top of it, [perhaps you could slot your rudder/elevator servos into it as well], velcro your battery beneath it, then fit a hatch on the bottom of the fuselage so that the battery can be removed without having to take the wing off. Cheers, Phil

[all_fly_all_day]

thanks once again phill, that sounds a lot better then my idea. But then im afraid that velcro might rip the board if its too strong, is there a way i can make a hatch strong enough and could hold the batt. pack so i could just build a spot for it under the equipment board where it wont shift around then use the hatch to hold it up? And what would be the best way to make a hatch without adding too much weight. Sounds like you might of done this before. I have a question about that DuBro 's "Micro Aileron system". The rods that connect to the airlerons and and servo look pretty short in the picture i looked at. can you order them in longer lengths? These ailerons are at least 20 in. apart i believe. I just remembered reading about people who use the "cable and tube" method. Two flexible cables run through tubing connected to the servo and then routed to the control surface. Then there's no need for bent robs and connectors anymore. Just a thought. If you have any idea where i might be able to find this setup. please let me know. Or if you think that would be the wrong way to go. I looked at the Solarfilm you recommended, and it looks good. We just have to come up with a good color scheme for it now. Anyone out there seen some pics online of basic colors on a skyhawk? Well, thats bout it for now. Im hoping we can get that material ordered soon. I remembered my grandpa has just read up on covering and he has done it before, so hopefully he can help us out with that. Thank you all




Brandon

[all_fly_all_day]

Heres the picture i was talking about. Those rods only look couple inches long to me....

[Dr Kiwi]

Brandon - I don't know about flex connections, but you can just get some lengths of the appropriate gauge wire (I'm guessing here, but .020 or .032 might do it) and bend it to suit. That way you can make the length of the aileron connectors, and if they need altering too, those from the servos, exactly what you need. As for the battery - you can surface the plate with 1/64" ply, then attach the battery with just some small pieces of velcro, not a full length strip of it. The hatch is a bit difficult since I don't know what the shape of the fuselage is - I made one for my Wing-E (see the thread for that), and a different type for my New Easy (today's post) - those might give you some idea. Covering with Solarfilm is a breeze - full instructions come with the material - just don't have the iron too hot or you'll melt it (practise on scraps to get the feel of it). Cheers, Phil

[Dave Robelen]

Hi Brandon,
I may be misreading your aileron connection question, but it sounds like you are planning to use one servo to drive the ailerons that are out on the wings, and do not extend all the way to the fuselage. If that is the case, the Sullivan company makes a 1/32" dia flex cable in a thin plastic tube that is normally used to drive the carburetor arm on a fuel job. I have had good success using this cable/tube system to drive seperate ailerons from a center mounted servo. The tube needs to be bonded to the wing ribs to prevent moving under load, and routed in a wide curve as it goes toward the ailerons. I put a control horn on the bottom of each aileron, and connect one cable to each side of the servo so that they move in opposite directions.
Take care, Dave

[all_fly_all_day]

Mr. Phill-
That sounds like a pretty good idea. I guess i wasnt thinking right and thought i would be putting a big battery pack in the body. But for a small one a lil velcro will be enough to hold it in place. Ill get some photos of our progress as soon as possible so help with visualizing the best hatch idea. Ill be thinking about it too.

Mr. Robelen-
You read the question perfectly. Thats what i was going for. but i assume you need to have some adapter on the end of the cable to connect it to the horn and servo :confused:. how would i go about doing that? wrap music wire with a "Z" bend on the end of it to the cable with thread and CA? Ive tried that thread and CA approach for landing gear wire and it just slipped off, CA and all. Should I sand it first? Or is that whole idea wrong:( .

And just a couple more questions, when covering tail surfaces do you hinge them first, or cover first? And should i leave the area where the surface gets glued to the fusalage uncovered for wood to wood contact? Well, thats about it for tonight.

P.S. Shhh, Dan, dont tell. but my friend and i took your advice and we're looking around for plans online to build our own scratch built plane. He's got a .15 and a nice radio set-up that he cant do anything with right now.:D that will be our summer project if all goes well.

Happy Flying
Brandon

[Dave Robelen]

Hi Brandon,
The joint between the two wires (cable and solid) should be soldered. Bind with a few strands of copper wire from a piece of lamp cord. You can use this stage to adjust the neutral. Than a little paste flux on the joint and flow solder.
The controls should be covered before assembly, and yes, leave them bare where they join with other wood.
Regards, Dave

[yeeehaw]

Brandon,

First off, I applaude your efforts and your patience. I have a friend like yours that is not the patient type, but he is not into rc. He wants to get the biggest plane at the hobby shop (mitsubishi zero) and he doesn't even know how to fly.
I have been reading this thread and your battery seems to be too heavy for that plane (8.4v 300mah capacity+2-3 micro servos)
You might want to go with a smaller pack (7.2v 270 mah)
I have not personally flown with these but you might want to check out lithium polymer cells or lithium ion cells. you can wire them into series and they are relitively inexpensive and 60% lighter. The charger will run you in the $$$ but you need a good charger anyway. The greatplanes Triton charger will cost you around 120.00 at towerhobbies. Or if you are like me (14 and prefer not to buy off the internet) go to your local hobby shop and ask them to order one.
I was wandering what grade are you in??
I hope this helps

Matt

[all_fly_all_day]

hey Matt, thanks for the ideas. I know i havnt posted here lately but moneys coming slow and we only build the plane on the weekends. Futhermore, he has banged up his Pico-Stick's wings and wants to order a replacement.:mad: Putting us even father back in money. He says they're beyond repair. But i dont think its possible with those GWS wings. Anyway, does anyone know where (online) i can find replacement wings? Ok, as for the battery, it is Ni-Mh, not Nicad. I wasnt sure if you caught that. but before we go off discussing battery packs, we have to know what motor where putting in the nose of this thing. A IPS motor might be ok. But im still afraid that it just wont have enough power to pull this thing along. And i have no clue on the performance of the dual IPS motors.:confused: I would think that two motors would pull the same amount of "juice" from our pack as a geared 280??? So wouldnt it be a better idea just to go for the 280 and add power. Even if it means a lil bit more wing loading? I guess it all depends on the final weight. Oh, Matt, right now im in 8th grade. Cant wait till HS.:D :cool:

[Dr Kiwi]

Dear Brandon - It's good to know that the project is progressing, if slowly! As you correctly discern, your possibilities for motors include the GWS EPU single motors, the GWS IPSD dual motors and Speed 280 or 300 motors. [You could go the brushless route, but if my own 8th grader came home and said he wanted a $150 motor and ESC for his plane I would have to tell him to dream on!]The RTF weight of the machine is of immediate concern, since the EPU motors probably aren't powerful enough for planes of more than about 7oz. Obviously the dual motors or 280/300's can cope with heavier planes, but since the laws of physics tell you that you cannot get something (i.e. more power) for nothing (i.e. you'll need more current). It is very hard to get comparable figures for these various motors, but for the GWS ones www.toddsmodels.com and www.aeromicro.com give you more info than does the GWS website. In the www.hobby-lobby.com catalog one can find some figures for 280's and 300's.

Here are some figures I have come up with which might help you decide which way to jump. For GWS I've used 6-cell figures (7.2v) since they doesn't recommend more than 6-cells and therefore typically don't provide data for 8.4v or 9.6v!


GWS EPU 4 (variously known as IPS-DX-1XC or S1) with 4.1:1 g/box + 9x4.7 prop (weight 36g), on 7.2v: - current draw 2amps, thrust 4.5oz, power 14W.

GWS IPSD-RXC-1 with 4.1:1 g/box + 9x4.7 prop (weight 48g), on 7.2v: - current draw 3.7amps, thrust 7.2oz, power 26.6W. On 8.4v and a 3-blade 9x7 prop you can suck 5A through the system and get 40W of power!

Graupner Speed 280 with 4:1 g/box + 9x7 prop (weight 66g), on 9.6v: - current draw 3amps, thrust 7oz, power 19W.

Graupner Speed 300 with 5:1 g/box + 8x6 prop (weight 72g), on 7.2v: current draw 6amps, thrust ?12oz, power 34W. On 8.4v: current draw is 8.6A and power 64W (thrust possibly 20+oz).

I think you will need to base your power choice largely on RTF weight: under 7oz you could get away with the EPU 4. Between 7 and 12oz the IPSD gives you double (or more) power for only a 12g (1/2oz) weight increase [but you'll use twice as much juice on full throttle]. Above 12oz you need to go to the 280, or better still the 300, which, with only 6g (1/4oz) more weight, gives you at least twice the power again.

Hope this helps rather than confuses you further, Cheers, Phil.





GWS EPU [DX-1XC or S1] with 4.1:1 g/box and 9x7 prop, on 7.2v

[yeeehaw]

Dude me too(8th grade):D
The wings you might want to check out www.horizonhobby.com or www.grandwing.com.tw I think twin IPS motors will draw as much juice as a geared 280 but you might want bigger motors, a little more juice draw, better aerobatics and you might be able to hover:D I am trying to get my s.stick to hover. It is all on what you want. Twin IPS motors will get you a rolling takeoff.
If you havn't got the IPS motors you might check the GWS stuff(EP 300c motor) Like I said it is all on what you want.
oh yeah try to elmers glue the wing to gether and tape it to gether.
I hope this helps.
Matt

[flyinhigh]

Hey AllFly
If you go with the 280 make sure it is geared...my cub weighs under 8 ounces and it moves right along but it doesnt like to climb to steeply.By the way an S1 with 7 cells seems to put out more thrust than the 280 with the 125x110 prop on it and flight times will be much longer.If you have Motocalc pull some figures from there if not download the trial version,
At this point your probably wondering how you will fit the motor in and knowing what motor you will use will make that alot easier..
I highly doubt your plane will weigh over 10 ounces,unless Guillows supplied you with some very heavy wood!
Good Luck
MIKE

[yeeehaw]

just wandering is there a gullows website??? I am looking for a new plane.
Matt

[Dr Kiwi]

Hey Matt - Amazingly enough there is a "Guillows" site [spell-check helps here!] it is www.guillow.com. There is one company which seems to specialise in Guillows kits: try this link http://www.sactoys.com/bybrand.asp?bid=118. Good luck with the building of "real" balsa aircraft (there is my bias again!). Cheers, Phil

[miraclesailor]

Matt:

Since you are thinking of making a bolsa kit, think about a scratch build. There is nothing like having a plane that came to you as balsa sheets. Look for a plane that is constant cord for your first project. To make things easier use a piece of plywood or plastic sheet for a template to cut out your ribs so they will all be very close. As for the fuselage, you could look for a plane that is bulkhead and strips but for ease look at a plane that uses few bulkheads covered with light balsa sheeting (box construction). This plane will be your favorite for a long time due to it being a first for you. It is really cheap to build as well.

If you would like to know more let me know. You did not mention what kind of plane you are planning to get as a kit. That would help in deciding on what to try as a real scratch built.

Later,
Dan

<<just wandering is there a gullows website??? I am looking for a new plane.
Matt>>