Art Hobby Thermic Questions...

[jrbackus]

I just bought an Art Hobby Thermic which is my first sailplane. Ok... it's my first airplane too... I have several questions (due to me being a newbie...)that I feel someone will be able to answer fairly easily.

1. What battery should I put in it??? I have seen people put Sub C as well as AA. From what I have read, these are light ships and the weight is not of huge concern (I plan on flying this for fun, not competition).

2. Should I cut flaps? I plan on mixing the ailerons as spoilerons but am torn with if I should cut flaps...

3. Next, I know spoilerons go up and flaperons go down... (as well as acting like ailerons) Why can't the control surface go both up AND down (therefore acting as flaps and spoilers) while still being used as ailerons??? Is it a problem with my definition or is it a physical thing that i'm missing???

4. Push rods... The pushrods that came with my thermic are TINY... I have heard of some people replacing them with more rigid control rods, I want to know what is the best here.

5. As for the DB9 connectors, do I have to use specific pins for the different wires or as long as I keep track of what pin connects what wire, it will be ok??? I guess allong with this, does a DB9 connector connect straight through???

6. Hinge tape... I was wondering what to use as hinge tape. I have some 3M "Mailing Tape". It is clear tape with fiberglass reinforcement strips running the length. It's REALLY strong and I was wondering if this would work. Also, I have heard of using 3M Super77 before sticking the hinge tape down. Is this something that is usually done??

7. Lastly, am I nuts for making this be my first airplane ever??? I have heard very good things about the ship and thought I would give it a try. Even if I can't fly it, I love building so it'll be fun either way :D

I appreciate ANY advice you can offer about the topics above or anything else that might be helpful. I'm new to all of this but it seems like it's going to be a lot of fun.


Jeremy

[Phil.Taylor]

Hi Jeremy - search in these forums for "Art Hobby Thermic" & you'll find lots of useful info, build threads etc.
FWIW - if its your first ever plane - seek out other flyers, the local club etc - they can help you get started safely without the otherwise inevitable broken bits & mending (can do it solo, but you may be fixing whilst learning! - did that 30+ years ago!). These days I recommend people start on an EPP foamy - it bounces - then progress from there.
Good luck - and have fun building & flying - its a great hobby
Phil

[jrbackus]

These are just the questions that I can't find definitive answers to on the other threads. I have read through the Thermic and Sierra build threads which were very helpful, but I still had several questions.

[Komet]

I just bought an Art Hobby Thermic which is my first sailplane. Ok... it's my first airplane too... I have several questions (due to me being a newbie...)that I feel someone will be able to answer fairly easily.

1. What battery should I put in it??? I have seen people put Sub C as well as AA. From what I have read, these are light ships and the weight is not of huge concern (I plan on flying this for fun, not competition).

2. Should I cut flaps? I plan on mixing the ailerons as spoilerons but am torn with if I should cut flaps...

3. Next, I know spoilerons go up and flaperons go down... (as well as acting like ailerons) Why can't the control surface go both up AND down (therefore acting as flaps and spoilers) while still being used as ailerons??? Is it a problem with my definition or is it a physical thing that i'm missing???

4. Push rods... The pushrods that came with my thermic are TINY... I have heard of some people replacing them with more rigid control rods, I want to know what is the best here.

5. As for the DB9 connectors, do I have to use specific pins for the different wires or as long as I keep track of what pin connects what wire, it will be ok??? I guess allong with this, does a DB9 connector connect straight through???

6. Hinge tape... I was wondering what to use as hinge tape. I have some 3M "Mailing Tape". It is clear tape with fiberglass reinforcement strips running the length. It's REALLY strong and I was wondering if this would work. Also, I have heard of using 3M Super77 before sticking the hinge tape down. Is this something that is usually done??

7. Lastly, am I nuts for making this be my first airplane ever??? I have heard very good things about the ship and thought I would give it a try. Even if I can't fly it, I love building so it'll be fun either way :D

I appreciate ANY advice you can offer about the topics above or anything else that might be helpful. I'm new to all of this but it seems like it's going to be a lot of fun.

Jeremy
Here are my thoughts, plenty of others may disagree though.
1. The battery is really up to you. I would look at the highest capacity battery pack available that can be fit into the fuse. The trade off is that you can’t go too heavy because you might find it difficult to get your CoG correct.

2. I would cut flaps. Spoilerons are great as a landing aid, but they don’t really slow the plane down, just cut lift. If you have flaps you’ll also have some pretty cool mixing options, like camber and crow braking.

3. With flaps the hinge is usually on the bottom to allow the most possible down deflection while ailerons/spoilerons are hinged on the top to allow more up travel.

4. I don’t know what kind of pushrods are supplied with the kit, but if you’re concerned about tem then it’s probably a good idea to replace them. You wouldn’t be the first person to toss out some of the included hardware in a kit.

5. Don’t know about the DB9 connector so I can’t help with that one. I think the important thing is that you make sure that the correct servo wires are connected.

6. I’d be wary of using a tape with fibreglass reinforcing unless you know it’s been UV protected. Anytime I’ve used similar types of tape outdoors it starts to break apart after some exposure to the sun. Once it does it can be a bit messy to clean up. There are tapes that are made specifically for hinging, I use often use Graupner brand myself, but I’ve also had good results using clear sticky tape. So far it seems to be holding up to UV exposure well. I don’t think you need bother with the M77, just make sure the surface is clean and dry. Remember you might want to remove the hinging at some time in the future for repairs.

7. Arthobby have a good reputation in both service and quality of their product from what I hear. My next plane will be from them, a High Aspect electric version. I think they offer pretty good value for money, so I would have to say that on the whole it’s probably not a bad way to go – particularly as you’ve already bought the thing! I would second the earlier advice that you get some help if you are new to flying. It would really hurt seeing such a lovely looking plane go in. Even though it’s a thermal glider it will still probably be a bit slippery compared to a floater type glider like a great planes spirit or a Gentle Lady. Overall. I’d advise you to go to a club. They’ll have bungie’s or winches there already and they’ll be able to help you learn to fly it

[CMNZ]

Hi Jeremy,

I have had a JK Thermic 2.5 V-tail for over 10 months now - great sailplane, great kit!

Here are my views on you questions;

1. I am using some AAA NiMH. There is not a lot of room so it depends on what you can get in - the bigger the better.

2. I did not cut flaps into mine - if you decide to you will have to also add some edge stiffening to the aft of the wing. If I built the model again, I would add flaps with 90 degree down for dive brakes.

3. My ailerons are mixed to go up for reflex and down for flaperons. On launch I dial in a little down and also when thermaling. Spoilerons don't seem to do a hell of a lot except make the ailerons ineffective. I big thermals it won't come down unless you fly inverted or crank it into a tight turn with full up elevator.

4. If installed properly as per the instructions the pushrods are fine and are plenty strong and rigid enough.

5. I used Deans connectors on mine, but anything that has at least three pins will do fine. They are just a servo extension lead so they connect straight through.

6. I taped mine with clear tape or Diamond tape - it does not have to be particularly strong provided you tape both the upper and lower sides. You could also try a silicon hinge.

7. I would say that this sailplane is reasonably easy to fly but.... it is not a floater. It moves around the sky pretty quick and has to be flown reasonably fast compared to a Spirit, Bird of Thyme etc. I have advised others looking at a first time sailplane to get the Thermic RES which would be a little more suitable. However, if you have some other sailplane pilots around they should be able to help you out.

Just set it up as per the instructions to start with - it will fly perfectly well like that until you are ready to start experimenting with the C of G etc.

Keep the model light, it will thermal better and penetrates well without any ballast. Be a liitle cardful on landings, don't spear it in. I have flown my in competitions with any problems or breakages but... I have seen the tail boom flex when landing on rough ground. When you cut out the access for the servos etc make the holes as small as possible - the fuselage relies on the material left in for strength and rigidity.

If you have any questions or want to see any pictures just let me know and I will post them.

Here is a really good build thread!
http://www.rcgroups.com/forums/showthread.php?t=315316

Good luck and have fun!

Alan

[jrbackus]

When you cut out the access for the servos etc make the holes as small as possible - the fuselage relies on the material left in for strength and rigidity.

If you have any questions or want to see any pictures just let me know and I will post them.

Here is a really good build thread!
http://www.rcgroups.com/forums/showthread.php?t=315316

Good luck and have fun!

Alan

Thanks for all of the adivce, I have read that build thread a couple times and that is partly why I ended up with the Thermic.

I would like to see your servo tray setup if possible. I have been looking into several different options and wouldn't mind another.

As for the hinges, I have seen 2 major methods:
First, running hinge tape allong the gap on the top and bottom. (usual method)
Second, making individual hinges out of a few pieces of tape. (http://www.yourzagi.com/hinges.htm)

I was curious if anyone had some input on these methods...

Finally, I have semi decided to cut flaps but I don't want to put more servo's in the wings. Has anyone ever put a single (or 2 for that matter) servo's in the fuselage of a glider to power the flaps???
It seems like you could easially run a piece of metal rod out the top of the fuselage, into the wing, then a 90 deg. bend into the flap. This way you can keep the weight in the fuselage and also only use one servo (as long as you want the flaps to move together).

I'm an engineer so maybe I will come up with some crazy idea but I was just curious if this had ever been done...

Thanks for the help!

-j-

[CMNZ]

Hi Jeremy,

I will take a couple of photos and post them tomorrow.

I personally would rather put the flap servos in the wings. The wings carry the load so it makes sense for them to carry the servos, if you put them in the fuselage, then the extra weight is putting the wing bolts and fuselage under extra load. I would also mix the flap with aileron so I had full length ailerons when the flaps were in their normal position.

Another item that you may want to consider doing is to replace the small locating pin at the forward wing mount with a bolt and hardwood block inside the wing, the same as the aft mount.

The advantage with the hinge tape is that it seals the join between the wing and aileron. After 10 months of flying most weekends I have only replaced the tape once, and then it was just as a precaution.

Alan

[moreil]

I would recommend the silicone hinges that were mentioned above.

I was skeptical, but tried these on my Castor (electric version of the thermic) and was very impressed. They're VERY strong, very flexible and UV resistant. They're also easier to make than it seems. Mine worked just fine very first try.

When I compare these to the tape hinges on some of my other planes, I'm planning to replace those with silicone too.

[jrbackus]

What type of silicone works well???

Btw, I agree with the fact that putting the servo's in the fuse is a bad idea. Getting the wing on and off would be really tough if you had wires AND pushrods to deal with.

-j-

[tclark]

Jeremy-
For a 1st plane, I would advise keeping the plane as simple and stock as possible. I wouldn't recommend flaps, for simplicity and also because this plane is plenty useful without them.

-Tracy

[CMNZ]

Jeremy,

Photo of the servo's and tray. The tray was made up of a CF/balsa/CF sandwich with small hardwood rails expoxied to the fuselage.

[kwmtrubrit]

I'm about to start my Thermic 2.5 and am interested in more info about the silicone hinges. jrbackus, as already mentioned, for you to put flaps on the wings you will need to place balsa in the wing and flap at the cut to add the necessary strength/support in that area. Are you sure you want to get into that? Build it with the flaperon/spoileron, fly it and see what you think. You can always add on afterwards. May the R/C gods watch over you.

Keith

[moreil]

The silicone hinges I learnt about here http://www.slopeflyer.com/soaring/html/tip/silicone_hinge.html

I used 'Selleys AllClear' here in australia, but the exact type of silicone doesn't seem to be that important. 'AllClear' is as per the name, a silicone used for holding glass togther (as in showers and aquaraiums et al) that dries clear.

I found it a fair bit easier than described in the link above, as silicone cures near instantly on the skin but takes literally days to cure all the way through. This means that it seems to better to put too much and the remove the excess than vice-versa.

Thus I used tape on the outside to hold the aileron and wing together, then laid down a think bead along the inside of the hinge (using FAR too much silicone in my inexperience) and then ran a scrap bit of balsa along the inside of the hinge removing most of the silicone and leaving a small neat bead remaining. (I was a little bit careful here: I cut a triangle of balsa that fitted the hinge angle, and then cut the tip of the triangle to match the amount of silicone that I wanted to leave. If that makes any sense).

A day later I removed the tape and ta-dah! all finished.

If you really really mess it up, you can just wait a couple of hours for it to form a thickish skin and then basically peel it off from one end.

I should also mention that I very initially used a couple of scraps of 5mm balsa, cut a bevel on one piece and practiced hinging them first.

[jrbackus]

From that website :

Open the control surface and run a bead of RTV silicone 1/16” - 1/8” (depending on the size of the control surface). This is done on the inside of the control surface.

I realize that i'm going to have a flat surface bonding to a beveled surface, but what do they mean by "open the controll surface"??? I feel as if I just lay a bead of silicone in the bottom of the "V" that is made by the wing and aileron (while the controll surface is in the neutral position) it would work.
Is the the recommended method??? Or should I actually open the gap (put the aileron in an UP position)??? I feel as if I did this the controll surface would be "stuck" in the UP position...

Anywho, if anyone can decipher what I am talking about, I would greatly appreciate some advice. Possible another web site with some more explination or pictures...

-j-

[moreil]

Yup, that's what I did.

I put the top of the wing and aileron flat on a surface, then put silicone in the V thus formed, and then wiped off the excess.