Build your own indoor:

The Huntington H12 (1922)

Why this model ? Simply because I like it and also because its plan can be found in a little leaflet headed "Les cacahučtes en polystyrčne" (Peanuts in foam) and published by Yves Guillemineau. I got it few years ago (my issue is dated February 14th, 1992) by means of Jacques Delcroix who presents every year many free flight models at the international model show in Paris (France). You will find in it many good advice and the full scale plan to build this Huntington peanut with polystyrene (Styrodur foam) and a rubber power (wingspan 33 cm - weight 10 grams). Plan : part 1, part 2.

Taking into account R/C equipment available today (2002), I decided to make this R/C indoor version at scale 1.41 (then surfaces are doubled). Therefore the A3 original plan has been enlarged to the A2 format by photocopy.

Of course, the method proposed herein can be transposed to any model of your choice and thousands of peanut plans are available : the main thing is to choose a model which appeal to you ! It should be also achievable by you without too many difficulties, but here, it is very relative and you are your own judge : it only depends on your experience and your skills.

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The real plane.

Information hereafter has been found on the site aerofiles.com where you will find also a 3-view plan and action art from an old ad.

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And now, go ahead !

The first thing to do is to enlarge the plan to the required dimensions and to paste it, or even better a copy of it, on a thick cardboard to make the templates. Templates of symmetrical pieces (fuselage top and bottom, elevator) will be foldable in order to be able to trim (sandpapering) both sides at the once and thus to obtain a perfect symmetry. Note the two templates to cut the ribs according to the "block method" and the big size of the dihedral template to increase the precision during assembly. Then the different pieces are cut in Depron sheets of various thickness : Fuselage : 1,5 mm. Wing : 8/10 mm. Rudder : 1,5 mm Elevator : 1 mm Ribs are cut in block with a thermal saw in standard 3 mm Depron.
Some few details.
Fuselage TOP is glued on the INNER side of the left side. Everything is glued with cyano glue (special polystyrene).	Fuselage TOP is flat and will be used as a reference during assembly. Bulkhead and formers are made of 3 mm Depron.	The block of ribs is ready for cutting. Templates are lined up with two toothpicks.	The foam cutting saw is vertically held in the bench and ribs are cut by hand.
The two wing spars are made of 1 mm carbon rods.	Motor mount : 3 mm Depron 3 mm stiffened by 4/10 mm plywood.	A 145 mAh battery (left) and a 135 mAh battery (right). The very fragile terminal strips are glued on a small piece of 15/10 mm balsa.	The battery on its support.
Bottom view. Motor bulkhead is held in place by the battery support used as a spacer. Everything can be dismantled.		Bottom view. Actuator pushrod is made of 0,5 mm carbon rods. The "Z-bends" are made of 0,5 mm brass wire.

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Actuators' assembly.

- 1st case : Actuator with direct control (rudder).

A 4/10 mm copper wire is sandwiched between two 4/10 mm pieces of wood and glued with cyano on the magnet.	The other part of the magnet is glued on top.	To improve the gluing on the rudder and increase rigidity, the copper wire is stuck between two thin Depron bands.	Actuator in place on the fin.

- 2nd case : Actuator with control arm (elevator).

The method described hereafter was firstly used by J.Y. Martin in his "Magicien d'Oz". Such remote actuators can be put inside the fuselage and thus make balancing easier avoiding extra weight at tail. It is also less visible which could be an advantage in case of a scale model.

A 4/10 mm brass wire is mounted as indicated above and will be used as the axle.	The inner side of the coil is protected by a paper strip.	An "U" of paper (2 layers set to shape and cyano-glued) is used as magnet holder. A control arm made of paper is also glued on the magnet.	The paper U with the magnet on it is put in place and glued inside the coil.

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Here it is !

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Suitable equipment

The range of micro-equipment available for these little models is extending progressively. MicroMag units (Rick Ruijsink -Holland) were among the first ones available. The RFFS-100 from Dynamic Unlimited (Clarence Hurd - USA) has the advantage of being well spread and easily available. The last one to come out (availibility September 2003), the Rx-Combo from JMP-Solutions (Jean-Marie Piednoir - France) had to be innovative and the best performing. Table below shows the main characteristics of these three units. You can download the detailed features of the Rx-combo from JMP-Solutions here on Microsoft Word format (French version and English version).

	RFFS-100	MicroMag	RxCombo JMP
Origin :	U.S.A.	Holland	France
Frequency band :	35 and 72 Mhz	27, 35, 40 and 41 Mhz	35, 36, 40, 41 and 72 Mhz
Selectivity :	+/- 76 kHz	+/- 20 kHz	+/- 10 kHz
Number of channels :	3	3	3 (4th ch. on option)
Dimensions (in mm) :	34 x 12,7	16 x 18 (Rx) and 10 x 10 (ESC)	30 x 12,7
Weight (in g) :	2	1,8 (Rx) and 0,5 (ESC)	1,7 (plus quartz 0,35)
Supply voltage (V) :	1,8 to 5,5	2,2 to 5	2 to 5,5 (11 V on option)
ESC included :	Yes (1A max)	No (1,5 A max)	Yes (1,5 A max)
Plug-in crystal :	Yes	No	Yes
Low voltage detection :	No	No	Yes
Mixer (delta wing, V-tail, etc...) :	No	No	Yes
4th channel option :	No	No	Yes
7,2 V option (2 LiPoly cells) :	No	No	Yes

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Conclusion

As I said above, this is only an example of what you can achieve using equipment which are available today (January 2003) but you will have to optimise for each model the balancing, the motor, the prop, the gear, etc...

In order to help you to adapt and build your own model, you will find below a table showing mass breakdown for a typical peanut (Extract from an article by René Jossien in the MRA magazine N°448 - March 1977) and the extrapolation to R/C model at scale 1.4. When you scale something at 1.4 it should be noted that surface areas are doubled but masses should be almost tripled (exactly 1,4 to the cube). In fact, if you build light (You are not obliged to multiply thicknesses by 1;4 as well), you should be able to get only almost doubled masses, as shown by the example of the Huntington described above. In these conditions, the wing loading remains unchanged. For more details on this subject, please click here.

Note : Peanuts, indoor free flight models with a wingspan less than 13' (33 cm), are within the F4F category. There is also in scale categories some other models, less known, called "Walnuts" with a wingspan less than 18' (45,7 cm). However, many "Walnut" kits are available and can be used for R/C conversion.