Lucas Hofman
-
Posts
1,183 -
Joined
-
Last visited
Content Type
Profiles
Forums
Blogs
Gallery
Calendar
Downloads
Everything posted by Lucas Hofman
-
-
-
-
-
Posted by kc on 19/12/2015 12:28:21: I am expecting ( well hoping ) that by moving the motor bulkhead forward about 1.75 inches on my model that a 4S 3000 lipo ( now able to move forward by that much ) will just about get the CG right without lead. And I have found a particularly light piece of balsa for the tailplane, fin and rudder. So I am expecting that your 4S2200 will not be sufficient weight- but I might be wrong! kc, I am not putting much money on it either. If the CG end up too far back I have 3 options. - open up the firewall so the battery can be placed partly in front of it. - use a 4240 motor (50 gr. heavier) - use a 3300mAh battery. I have both 2200mAh and 3300mAh batteries, and will wait with ordering the motor until the model is build.
-
Posted by Peter Miller on 19/12/2015 14:19:33: I think that I want to cry!!!! Why can't the pillock draw the plans right. He obviously doesn't know how to use his computer. What really makes me furious is that when people build the models I get the blame for errors not the (words fail me) draughtsman who can't stick to the original drawing. Peter, would it be possible to get a pdf file of your original plan. I would prefer to build your Ballerina, not the RCM&E draftman's....
-
Posted by McG 6969 on 18/12/2015 19:29:00: Lucas, Are you intended to move your battery box up to F5? In that case you have to move the servo tray as well, right? If you stop your battery tray at F4 & move F1 around 40 > 50 mm forward, - depending on your motor length -, you have plenty of space to shuttle your battery around & no need to shift your servo position. Just a thought. Hi Chris. No, the battery plate will stop at F4. But I think it is easier to make the hatch big. Easier with thick fingers and battery leads. Servo's will be up to F4 as drawn. Moving F1 forward makes the fuse heavier, and the sides just longer then one sheet of balsa. I think it is not needed. The next post will explain how I think it can work.
-
Posted by Geoff Sleath on 18/12/2015 20:32:29 Well I've gone for an SK3 4240 740rpm/v and a Plush 60 amp esc and I'll probably use a 3600 maH 4S LiPo. My first ever trip abroad back in 1966 was to Norway. We went in my then girl friend's mini and it had to be craned on and off the ferry on the way from Newcastle to Bergen. We did it on a the then £50/person travel allowance but it proved a very expensive trip - I proposed a week after we got back Beautiful country. It may very well be that I need to add weight in the nose to get the CG right! Then I can first use a bigger battery or step up to the 4240 moter. We will see! Nice to hear that something good came out of your trip to Norway!
-
Posted by Peter Miller on 18/12/2015 19:08:15: Posted by Lucas Hofman on 18/12/2015 15:47:59: Peter can design a whole plane and get the C.G. right. I cannot so I'd better make a big hatch so the battery Edited By Lucas Hofman on 18/12/2015 15:52:53 Edited By Lucas Hofman on 18/12/2015 15:54:14 More luck tnan good judgement! I keep a lot of lead in stock just in case Consistent luck = compentence. It is the same in F3A competitions: the same pilots correct just right for cross wind. If you ask them how the do it they often cannot tell you. The "just know".
-
Posted by kc on 18/12/2015 19:03:49: Lucas you may be interested in my thread " Prima Ballerina" which is also electric. Note that it has been stated that the dowel hole in F2 is placed rather too low and that it should be 1/2 inch from base rather than 1/4 inch. Actually drilled a little higher to allow filing to fit wing. Dowel slot in ribs should be altered too. This thread covers this point and also mentions changes to grain direction KC, I am following the Prima Ballerina thread. And thanks for the summary of errors to the printed plan!
-
Posted by Chris Barlow on 18/12/2015 16:56:29: Where abouts in Norway are you? Haslum, a suburb a little west for Oslo. It is a big country so we drive far to the various events and competitions. But often those drives are through beautifull mountain area's so that is part of the fun. Edited By Lucas Hofman on 18/12/2015 22:43:43
-
-
-
Since this will become en electric ballerina some thinking is needed. That should be allowed before Januare 1st without incurring the wrath of BEB I hope. I am keen on a program called motocalc to play around with batteries, motor and propellers. This has resulted in the following for the powertrain Motor: Turnigy SK-3542 800 kv ESC: 45A Propeller APC 12x8E Battery: Turnigy 4S 2200 mAh. This results in a weight saving of 200 grams compared to the prototype. I hope to be able to shave off another 100gr to achieve an AUW of 1700-1750 grams. Max power with this combination in will be around 500W and max thrust should be about 2000 grams. Expected flying time 6-7 minutes with good throttle management. The local copy shop makes pdf files of the plan, which I can print out to pencil on. First find a place for the battery plate: Peter can design a whole plane and get the C.G. right. I cannot so I'd better make a big hatch so the battery can move around. Roughly from F1 to F5. That means F2 need to be split, and the opening extended downwards: Edited By Lucas Hofman on 18/12/2015 15:52:53 Edited By Lucas Hofman on 18/12/2015 15:54:14
-
To understand the modifications to Peter's design it may be useful to do a short introduction. I started aeromodelling four years ago, and only fly electric. Most fields are electric around here. During the summer season I participate in F3A competitions, which strongly influences my flying style. Geometrical, gracious and not keen on "low and risky". During the winter (which is long and very dark here in Norway) I try to build a bit. Nigels Tucano was my first (although a year or two late to join the mass build) but this year I will try to join the pack. It is the first time I do a build thread here on modelflying so moderators, please let me know if I misbehave. Well, let's get started.
-
Posted by Peter Miller on 17/12/2015 13:44:52: Well you could use micros on the ailerons but and a BIG BUT. Only use metal geared servos. Unless of course you are happy to lose a flying session because you knocked an aileron on the way there. Personally I think you want more than micro servos on the elevator and rudder but they can be any reasonable make. I just like the Hitec ones. Hitec is always a safe bet, I have used quite a few of them. However, I do not agree with you on the metal gear part: metal geared have often more play in the gears compared to carbonite gear. And sloppy gears result in an less defined center, with feels as if the plane is never completely trimmed. I have only once had a stripped gear and that was after a crash, so that may explain my preferences. However, could it be that servo have to endure a lot more in an I.c. model due to vibration? Edited By Lucas Hofman on 17/12/2015 21:41:54
-
Has anybody already contemplated different servo's? For a not overpowered electrical Ballerina standard servo's seem overkill. Good quality (read non sloppy, good centering) analogue mini's (25-30 gr) will I think do the job for rudder and elevator, with micro's in the wing. I have not to bad experience with: TGY-9025MG: micro size, 1.8kg, 0.09s, 11gr TGY-9018MG: micro size, 2.5kg, 0.1s 13gr TGY-3317: mini size, 3.0kg, 0.14s, 26gr. Simple servo, but has performed well. Bit slow (but so am I..) These where bought a while ago, and there might be better options now. Of course Hitec servo are generally always good, but quite a bit more expensive. Anybody already thinking about servo's?
-
I will try to build so light (especially at the back end) that a 3542 motor will do. In that respect I wonder if the 1/8sq spruce could be replaced with hard balsa. Peter, what do you think?
-
I made a little spreadsheet that may help sort a mixed stack of balsa sheet into hard/med/soft. I found it usefull sorting through my stuff and relabeling it. You can find it on http://www.modellflynytt.no/attachment.php?attachmentid=84024&d=1450279319 Save this to a file and open it in Excel. Edited By Lucas Hofman on 16/12/2015 15:30:09
-
I am in. Having pestered Peter with questioned about more than one of his design I owe it to him to build one. Most likely a late start, since decent balsa cannot be bought in Norway anymore.
-
Posted by kc on 27/11/2015 19:18:09: After a quick look at the plan this evening I have drawn up my estimate of the main materials needed. Obviously this is unproven and just an estimate. You should check for yourself before placing an order for balsa! Balsa all 36 inch long 1/16 by 3 1 sheet webbing. 1/16 by 4 5 sheets wing sheeting + fus underside 3/32 by 4 3 sheets fus sides & turtle deck 3/32 by 3 3 sheets wing ribs 1/8 by 4 2 sheets formers, fus under & Leading edge 1/4 by 4 2 sheets fin tailplane rudder & aileron spar 1/2 by 4 half sheet (18 inch) cowl 1/4 sq hard 6 strips main spar & aileron spar 3/8 by 1/8 2 strips Trailing edge stock 1/2 triangular 1 strip Ply and spruce. 1/8 sq spruce 6 pcs 36 inch 1/32 birch ply 18 inch by 12 1/8 birch ply 8 inch by 10 inch 1/4 birch piece 3.5 by 4.5 inch 1/8 Liteply piece 9 inch by 12 inch 1/4 dia dowel piece 1.5 inch Edited By kc on 27/11/2015 19:48:14 kc, thanks for doing the counting for us lazy guys! However, I am missing the grade (soft, medium, hard) for the balsa. Or have I missed something?
-
Is the $ over the 4 on your keyboard Peter? Is the profile chosen the result of an analysis or is the a profile you always use for sport aerobats?
-
Peter, what is the profile you have chosen for the Ballerina wing? I apologize if you wrote about is in a thread here or in the RCME article, but I do not recall having seen it.
-
Suggestions for Peter Miller plans
Lucas Hofman replied to Fanyak's topic in Peter Miller plan builders
Thanks for the tip Peter. Amazon had a copy for USD 10!. -
Suggestions for Peter Miller plans
Lucas Hofman replied to Fanyak's topic in Peter Miller plan builders
Nearly all RV3 have a 2 bladed prop. Quite big looking at the pictures. A google search on RV-3 propeller results in a 70'' prop for a Lycoming O360 engine. on 1/5 scale this becomes a 14'' prop. on 1/4 scale 17''. 16x12'' will do fine for a 1/4 scale with a 5 cell setup and a 410kv motor according to MotorCalc.
