RC India

Inspired by the Tiger build by Mjet, decided to build one for a 60 size engine.Plan shared by Mjet was printed at 400% magnification to yield full size printout. This build will be a slow one.

Query: The total wingspan is 70 inches but the left wing is slightly bigger (90 cm) as compared to left wing (88.5cm). Mjet feels that there is an error in the drawing. Is it an error or deliberate to compensate for the engine rotation? Expert comment please.

This one (Phoenix)?
http://phoenixmodel.com/Product.aspx?ProductId=19 (http://phoenixmodel.com/Product.aspx?ProductId=19)

No. It is a Carl Goldberg design. Mjet has posted a build log on the forum. He had built it for a 46 siz engine. Mine is just bigger for a 60 size.

Seen asymmetric wings only on C/L like Bluepants (remember?)
Except maybe one Blohm & Voss - truly asymetric!
http://www.militaryfactory.com/imageviewer/ac/pic-detail.asp?aircraft_id=781&sCurrentPic=pic1 (http://www.militaryfactory.com/imageviewer/ac/pic-detail.asp?aircraft_id=781&sCurrentPic=pic1)

We have built two tiger and they flew well, very stable and you will love to Fly this model.if you see the wing at centre ,  misaligned centre is easily visible.

Control line planes generally have a larger left wing (with extra lift) to compensate for the weight of the control line. But why for a rc plane?

Can't believe it's intentional.

@ashok baijal
http://www.mikrovisions.com/plans/T60.pdf (http://www.mikrovisions.com/plans/T60.pdf)

Yes. Same plan but when printed out, the difference can be seen. Better to follow plan for the left wing and repeat the dimensions for the other so that they are symetrical

Yes you can go ahead with symetrical wings and belive me, that you will love to fly this model.

What about the formers which are missing in the plan??

I had taken the measurement and cutted from ply.

@Mjet.
The fuselage is box shaped, so formers will be rectangular. I will measure the width and height from the top and side views. Is there an alternate method?

The plane is pretty huge - The plan literally overflows the dining table.

To begin with, I traced the wing rib on a piece of paper and then after being satisfied with its size relative to the plan, I traced 16 ribs on 2.5 mm balsa sheets. 3 sheets used.

Next step was to roughly cut the ribs. After drilling two guide holes on each rib, they were held together using two bolts. A bit of sanding and all ribs were sanded to the same size. Next step was to cut the slots for the wing spars. This was done while keeping the ribs bunched together so that all the slots stay aligned.

Subscribed  :thumbsup:

Wow,
eagerly waiting for big plane

Ashok: Method is correct for formers.

As I received replies from experts of Tiger , wings is symmetrical and have same span. Its only a scaner issue.

Subscribed! Seems interesting. Best of Luck sir  :thumbsup:

I am documenting the build in detail. Maybe boring for experienced builders but could be helpful to new builders making balsa planes.

Take a soft board which is mounted on a hard surface. Mount the plan and cover it with butter paper (Waxed paper) or polythene sheet. Attach the lower spar using pins affixed in a cross pattern on the plan. This will serve as an index for the ribs. Since this is a symmetrical wing, the ribs are not flat on the underside. To avoid any warp in the wing, slide a strip of balsa on the aft side of the wing to serve as a support for the ribs. This will ensure that all ribs are level.

Next step is to align the ribs to the plan. Pin the ribs and ensure that they are vertical. I use a small right angle block to support the rib while I pin it up to the board. Method of pinning is visible in the attached image. Next step is to slide in the top spar. Put some cynoacrilate glue on the joints. Commonly available cyno is of the thin variety. While cutting the joints it should be ensured that the gaps are minimal. If some gap is there fill it was balsa sawdust before putting in the cyno. Dust off excess sawdust before putting in the cyno.

Next step is the glue in the leading edge. Since slots are pre-cut in ribs for the leading edge, the leading edge should align easily. Start by gluing in from the centre rib and glue outwards. This would be followed by gluing the trailing edge. Tack glue the centre rib first followed by tacking the outer two ribs. Thereafter glue each rib.

Once dried, take off the wing from the board and inspect each joint. Add cyno wherever necessary.

Next step is to build the shear webbing. The grain direction of the shear web should be vertical. Affix balsa sheeting as shown. I prefer to fix the web first and cut it after it dries off, rather than cutting it first and affixing it thereafter. Both methods work. Soon you will have all the shear webs in place.

Though not required, I am attaching the shear webs on the inner side also as I have used balsa for the main spar and not a hardwood like spruce.

What is the material of spar? Wood or Balsa and how you have prepared, pl post in detail.

@Mjet
Spar is 10mm balsa square - top and bottom. Will be reinforced by a carbon strip to be affixed before the sheeting of the leading edge.

Affixed carbon strips on the top and bottom spar. Attached sheeting to the trailing and leading edge.

Traced out the wing tip on 3mm balsa sheet. Cut slots in the leading and trailing edge and after sliding in the wing tip, glued it down. Ensured that the wing tip aligned with the centre of the rib. Sanded down the leading and traiing edges.

Important lessons in this thread for novice builders.

Pl post more pics of carbon rod, how and where you have fixed.

I have used 2 strips of 3 mm flat carbon strips on the top and lower spar. The strips were sourced from HK. I affixed them using cyno though araldite would have been slightly better. (www.hobbyking.com/hobbyking/.../__15385__Carbon_Strip_0_5x3x750 (http://))

Will Love To See The Plane Video Soon.
Regards,
Aman.

Took two aileron strips and sanded down the edge as shown below to enable free movement of the aileron. Made a mistake of sanding the full length. Later I cut off the required length of the aileron as per the plan. This should have been done before sanding off the edge. I then cut off two small pieces to fill in the edges. I had to sand off the shaped edge and affix a strip of balsa to prepare the end pieces. I could have avoided adding the strips, if I had not shaped the edge before cutting of the arequired aileron piece.

@aman
This will be a slow build because I come home for only a few days each month and only them I do some hobby work. I don't see an early end to this situation.

Cut off two pieces of 3mm lite ply for supporting the aileron servos. Holes for the servo are around 1mm bigger than the servos so that vibrations are not transmitted to the servos. Servos will be supported by small rubber pads to dampen the vibrations which are normal for glow powered rc models. Next cut off a slot in the vertical shear web so that the  servo plate is supported by the lower spar and then glued in the servo plate in both the wings. The model calls for two independent aileron servos, separate for each wing.

Going out again  :(. Build will resume on return.

great.. :thumbsup:

I have been followin this very excellent build with great interest. All the best Ashokji

 Thanks. Though I would love to complete the build as early as possible but unfortunate circumstances have forced me to stay away from home. Four walls dont' make a home though! No solution in sight.  :-\  :(  :( :(  :-\

best of luck along with lot of hardwork

Came home for two days. Suspending work on joining the two wings as I have to first create space for storing the wing before I can continue work on it. So started work on the horizontal stabiliser. I have shown step by step the way I arranged the pieces cut off from 10mm balsa for making the stabiliser

Remaining pieces

Once all pieces were in place, used cyno to glue them up. The stabiliser was taken off the plan and the edges were rounded. The elevator piece was cut off from a 10mm balsa sheet and the edges were sanded to give a rounded profile. As per the plan, the elevator is in two pieces joined in the middle. I therefore cut the elevator into two pieces. A piece of hardwood dowel was used for joining. V shaped groves were created in the slot and the dowel epoxied in place. I used the edge of my work table as a guide to keep the two pieces aligned and since it is a glass top table the two pieces will be aligned in the same plane. A twist in the elevator is what is not needed.

This weekend built the vertical stabiliser. Simply layed out the sticks on the plan and once satisfied stuck them with cyno, I then sanded the piece for glue marks and rounded the edges. I also covered the pieces with white covering material.

Started building the fuselage. Decided to try out a totally new material for a 60 size plane. Will be trying out building the fuselage with 5mm biofoam. Sounds crazy!

Started by cutting the panels out of 5 mm foam. Since a glow engine creates a lot of vibration, the cabin section needs to be reinforced with ply. So cut two pieces of the cabin area from  3mm ply.

Next step was to apply fibre glass to the side biofoam panels.Fibre cloth was cut to match the shape of the panel and fixed using thinned out araldite. I used methnol for diluting the araldite. After pouring the mixture on the fibre cloth, it was spread using a piece of formica board. Any piece of stiff card would serve the purpose.

After trimming the extra cloth, the ply reinforcement was fixed on the inner sides. At the same time, the rear part was also covered with fibre cloth. Once dried and trimmed, the two pieces were clamped together and edges sanded so that the two pieces are exactly similar.

After marking the loaction of the formers, cut out the formers for the two cabin ends. These two pieces were fixed  using araldite. The fuselage side pieces wer held in place using rubber bands.

Which Araldite? Slow or rapid?
How did the methanol affect it? On strength. On drying time.
I've been using 20 min Finish Cure epoxy from Bob Smith Ind, USA, via Hobby King,
Or Nerolac Wonderwood.
If Araldite 5 min can be thinned with methanol, and sets within say 30 min, it may be cheaper and faster.
Mention weight of fibreglass too.
Your experience will help many experimenters.

I had used Araldite Standard. Had read somewhere that it can be thinned with alcohol. Since methnol is from the alcohol group it worked. After application, the methanol evaporates and leaves the epoxy behind. The fibre glass cloth was lying with me for the past few years. So do not know its specs.

A thin version of Araldite is available in Mumbai, best suited for this work. I had seen a modeller using it while making a boat. The hardner for this variety is mixed by weight instead of by volume. I can try and find out the exact name of this version of Araldite through a common friend. It was a number and so I have forgotten it.

As for the strength, I can easily hold the fuselage in a horizontal position by holding it at the rear most end. Once the upper and lower pieces of the fuselage are fixed the plane should be adequately strong. I have earlier made a P51 (46 size engine) using biofoam, paper instead of fibreglass and covering in the end with vnyl. The plane has survived a few crashes.

Last weekend joined the two halves of the wing. Drew the outline of a joiner strip with a 4 degree dihedral. Next cut the oiner strip of 10mm  balsa. A slot was cut in the two centre ribs and the balas strip glued in. The joint was reinforced with ply braces on the two sides. Next step was sheeting the wing leading edge with 1/16 inch balsa. The central section was sheeted with thin ply.

A dry fit of the components was done today. A few more weekends of work left.

Coming up beautiful sir. Really getting motivated to build a similar one for my newly recd TT 0.061.

EDIT : Thanks to Iyer Sir's accurate observation below correctly amended to TT 0.61.

@sundaram sir,
A 0.061 sounds like a Norvel instead of a TT ;D

Thanks sir corrected. That's goes to prove how much I am in love with 1/2 A size.  ;D

Thanks Col. You have a beautiful engine. I will be using my OS 61. Is this a stock muffler or bought separately. Looking for this type of muffler for my TT 30 heli engine as I would like to shift my raptor to a  Bel222 fibreglass fuse I had purchased some 6-7 years back.

Sir the Engine is slightly used but in excellent condition and compression came with this muffler recently from the original owner Parambir (http://www.rcindia.org/profile/?u=4306) as a gift. I think he bought the muffler from towers.