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De Haviland
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Re: The various divisions of Free Flight models
Reply #4 - Feb 1st, 2019 at 9:29am
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Great info for us newbies !   Would be nice if there was a decent book similar to the late Don Ross's Rubber Powered Model Airplanes but with detailed additional information on the various divisions.   A book with lots of photographs would be even better.     Alternately, an e book would be a cheaper proposition and could be a collaborative effort.
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Re: The various divisions of Free Flight models
Reply #3 - Sep 22nd, 2018 at 7:32am
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Thanks much for adding a forum section for a model type that many of us find attractive. This is an excellent summation of the necessary info that we need to begin dimer projects.

Nice job!!
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Re: The various divisions of Free Flight models
Reply #2 - Aug 30th, 2014 at 9:30am
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Dime Scale...

Here's some more details I found on HPA re: "Dime Scale" size models:
Don't count on the retrieves being short. I once flew my lightest dime scale model outside and it caught a thermal. I ended up wading through a stream up to my neck to retrieve it. If I could have retrieved faster, I might have won the event. Since then, that one has flown only inside. Some of the Guillows designs had very light construction. For the others, if you use the lightest decent wood you can find (like 5 or 6 lbs), it may still be strong enough, especially for the smaller models.

I was curious and tried to find the bit about not scaling on the MMM web site, but I couldn't. IMHO, although I don't think it is in the rules, scaling an old dime scale design is not kosher. Not so sure about fudging around with a Mooney plan to  make it dimish, but perhaps MMM have own rules on this.

Dime Scale rules seem a bit squirmy. The latest seem to say plunge canopies are ok. There is something in the bonus points about compound curve canopies made from flat sheet, but that seems contradictory.

Latest FAC dime scale rules are posted here:
As of version on web site on Dec. 23, 2012:
Dime Scale models come in two flavors: Traditional, and Pseudo. Both compete under the same rules.
Traditional Dimers are built from plans produced during the “golden age” of modeling; Pseudo Dimers are built
from contemporary designs that honor the methods, structural simplicity, and details typical of those early plans.
A. Dime Scale models are to be of simple design and easy construction such as those built from 10 cent kits or
plans representing full scale airplanes built prior to December 31, 1949.
B. Wing span: 16 inches maximum.
C. When a Pseudo plan is created, the plan size is limited to one sheet of 11 X 17 inch paper plus one
8.5 X 11 inch parts page with engineering and details in the spirit of the original era.
D. Props must be one piece wood or molded plastic.
E. Model and plan must be presented to the CD prior to first flight for static pass/fail judging and awarding of
bonus points as described below.
Combining Traditional and Pseudo dimers involves some unique considerations. “Traditional” Dimers must
be built as per plan; however, contemporary construction modifications as listed below are permitted to ease
construction and increase the model's fun factor.
A. General construction:
1. Minimum wood size:
a. Greater than 14” wingspan: 1/16" thick sheet or square sticks.
b. 14" or less wingspan: 1/32" thick sheet and 1/20" square sticks.
c. Stiff paper called for on some plans may be replaced by 1/32" sheet or stringers with tissue.
2. Butt joints on plans, and landing gear struts may be reinforced with wire, sheet balsa or 1/32" ply.
3. No use of foam.
4. No vacuum formed or plunge molded parts EXCEPT canopies; SEE item 3.0-C "Dime Scale Bonus
Points" below.
B. Fuselage:
1. Pseudo Dimers must be engineered with box girder fuselage with formers.
2. The nose on Traditional dimers may be altered to accommodate improved thrust bearings and
removable nose plugs.
3. Rear motor peg may be located anywhere within fuselage or nacelles.
C. Wings and tailfeathers:
1. Wings may be one piece with spars added or moved. One piece stabs and rudders are permitted.
2. Stab and rudder may be reduced or enlarged moderately.
3. No laminated, wet / hot bent square balsa strip or otherwise "formed" curved balsa tips.
4. Wet / hot bent or “formed” bamboo tips are O.K.
5. Sheet wood may be substituted for bamboo tips called for on some traditional dimer plans.
6. No sliced or cracked ribs.
7. No under cambered wings unless shown on original era plan.
D. Dihedral (Traditional and Pseudo):
1. 1" max per side for models with less than 14" W/S.
2. 1.5" max per side for models with 14" to 16" W/S.
E. Coverings:
1. Double covering required unless original era plan specifically states "single covering."
2. Single covering OK if original era kit supplied just one set of wing insignias or markings.
F. Any color and markings on an original era plan may be changed to another era-appropriate combination.
A. Models will be “judged” solely for fidelity to plan, both in construction and scale detail. If a detail is on the
plan, it must be on the model. “Judging” is strictly pass/fail, in accord with the event rules.
B. Dimers are not to be held to the same standards of scale fidelity or craftsmanship as FAC Scale models. No
scale points are awarded.
C. Dime Scale Bonus points: cumulative when model meets multiple criteria.
0 High-Wing Cabin and Shoulder-Wing Monoplanes
1 Landing Gear Down and Dirty
2 Compound curved / bubble canopy from clear flat sheet material, i.e. P-51D
3 Parasol
5 Mid-Wing (see Appendix A: Determining Mid-Wing Status)
5 Canard or Tandem wing
10 Low-Wing
10 Float Plane
15 Biplane
20 Triplane
20 Multi
« Last Edit: Nov 11th, 2017 at 5:00pm by Sky9pilot »  

Dimers_facnwltr_1_julaug_001.jpg (Attachment deleted)
( 285 KB | 77 Downloads )

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C.L. Chennault

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Re: The various divisions of Free Flight models
Reply #1 - Mar 24th, 2012 at 2:01pm
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Tom, thank you very much for posting that. I have never seen all the info in one place like that.   


What does THIS button do?.........
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The various divisions of Free Flight models
Mar 24th, 2012 at 11:05am
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Have you ever been confused about the various classes of free flight models...

Do you know the  difference between a pistachio and a walnut or peanut....

Here's a Post from Yak52 on Hip Pocket Aeronautics site-There are a lot of terms bandied about aren't there?

All these classes originally came about from various competitive events organised by different organising clubs or bodies, for instance the FAC (Flying Aces Club), FAI (International), AMA (US), BMFA (UK) etc.

The different classes can first be broadly divided into scale or non-scale.

So to start with Scale - the 'nuts' are all scale models of different sizes:
Pistachio = 8" wing span
Peanut = 13" wing span
Dime Scale = 16" wing span  see the Dime Scale details on page on other page.
Bostonian = 16" wing span 14" fuselage length (see board for detail rules) Click Here
Edit 9/3/2019
VIII-1.0 NO-CAL PROFILE Competition for recognizable profile scale models.
A. Design considerations:
1. Wing span: 16 inches maximum.
2. Aircraft with fixed landing gear must have each landing gear represented as per the original subject.
3. All wing struts must be on the model.
4. Motor sticks shall not exceed fuselage length, however, the prop may be positioned at the tip of a scale profile spinner if
the real aircraft featured one.
5. Surfaces may be single covered.
6. Canopies and windows may be represented with tissue or paper; clear material is not required
7. Model must be in correct color scheme, and have control outlines, registration numbers, etc.
8. Have proof of scale. Judges decisions are final.
B. Official flight: 20 second minimum; NO MAX!
C. Scoring: Total of three flights.
Walnut= 18" wing span
Jumbo = 36" or greater wing span
A. FAC Rubber Powered Scale Events #1-4 are classified by wing span, as follows:
1. FAC Peanut Scale: 13 inches maximum.
2. FAC Rubber Scale:
a. Multi-wing: Greater than 13 inches, up to a maximum of 30 inches.
b. Monoplane: Greater than 13 inches, up to a maximum of 36 inches.
3. FAC Jumbo Scale:
a. Multi-wing: Greater than 30 inches b. Monoplane: Greater than 36 inches
4. FAC Giant Scale:
a. Multi-wing: Greater than 36 inches b. Monoplane: Greater than 42 inches
5. FAC Pioneer Scale (Event #5) has no wing span restriction. Limited to aircraft that were produced before 1914.
a. When no Pioneer Scale event is listed, Pioneer models will compete according to wingspan in FAC Rubber
Scale events #1-4.

Coconut scale, which remains very popular, but is pretty much only flown at USIC. Coconut scale is basically FAC Jumbo scale, but with no construction limitations and the requirement for ROG flights (not a severe limitation for a lightweight indoor model).

Then there are other scale classes such as Dime Scale (an FAC 'simple' scale class of 16") or 'BMFA kit scale'. Often size and power type are define the class. Rubber, CO2, Electric Rapier etc.

Duration models (non-scale) can range from indoor microfilm models right through to high-tech, high-performance outdoor models. Classes are determined by the FAI (international body) or some other similar countrywide organisation. They are usually classified by power type, size, wing area, weight etc.  Some of them have a long history such as Wakefields, Mulvihills and are named after their original competition trophies.

Then there are popular duration 'classes' such as Embryo, Bostonian, Legal Eagle, that are deliberately kept simple to promote wide participation. Bostonian is a 16" class with a requirement for a certain fuselage volume and a minimum weight of 7g indoors or 14g outdoors. Because they are a 'fun' class they often have some scale features like windscreens for instance.

Finally there are the classic models which are usually classified by age of the design. These are governed by SAM (Society of Antique Modellers). Click here for the "SAM" site
SAM calls models from the period prior to 1939, "antique", and prior to 1942, "old timer". I believe "vintage" is pre 1950 and post 1950 is known as "nostalgia".

The Free flight gliders seem to have developed their own acronyms based on launch technique. CLG (Catapult launched gliders) HLG (Hand Launched Gliders & Tip Launched Gliders) TLG (Tow Line Gliders).

Edit 11/17/2014: Legal Eagle - These are usually indoor models that must have the plans for the whole plane fit on a "legal size" sheet of paper (U.S. 8.5"X14") Thus the name "Legal Eagle". More info here: Click Here
« Last Edit: Oct 29th, 2020 at 4:49pm by Sky9pilot »  

If God is your Co-pilot...switch seats...
Your attitude will determine your altitude!- John Maxwell
And ye shall know the truth, and the truth shall set you free. Jn 8:32
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