maximum weight of RC gear for a RC convertion

[Bill Gaylord]

Hello Bill,

reading your reply I thought my original comment must have came across as rude. That wasn't my intetnion and I apologise if it did. I'm sure your models fly great in the hands of an experience flyer.

I don't post any of my stuff here, as I don't build Guillow's models, only scratchbuilds.
I don't want to spam in this thread, but I can send some example in a private message

Regardless, I don't think the figures I quoted are unrealistic, many conversions that you can find on rcgroups are much lighter than I could achieve.

You stated 8.2oz/sq-ft wing loading, for the 1/16 series models, which appear to be the OP's topic of dicussion. On average, with the exception of the Spitrire, 100sq-in would be a generous figure for wing area, which equates to about .7sq-ft. While no models care for less than ideal landings, to a point,a heaver model would actually have a better chance of resisting damage from a less than perfect landing. Optimizing that trade off is one of the main things I've learned, in converting a number these models. The advantage of the ultra-light model would be a scenario where the model dives into tall weeds after a total loss of control. At your weight figure, it would be fragile, for an average less than perfect landing, although the benefit would be that a good flyer should be able to land it easily.

Back to the wing loading, at .7sq-ft area, the r/c converted model would have an AUW of around 5.75oz. That's unrealistic for the 1/16 scale Guillow's warbirds, especially for a less than expert builder that is not substituting contest wood for the 1/4" stock, and minimizing all aspects of the gear weight, achieved by 100% efficiency in sizing and placement. The point I was making is that when I was relatively new at this, I was getting good results at higher weights, which would be expected from most newer builders. Look up 400 series conversions with only mild nose inset planking built by experience builders, compile stats, and you will find that the AUW is far above 5.75oz, probably more in the 8-9 oz range. Providing figures that are not documented from a practical experience with the models in question is not helping anyone. As for providing relevant reference info, I doubt anyone would consider it spamming, and would consider it valuable reference data.

[dirk gently]

Good point.
A 1/16 scale Bf-109 has wing area of 0.67 sq feet. Here's my example of a comparable model with roughly 0.59 sq. feet of wing area (excluding tail surface):






As you can see, it's partly sheeted, with capped ribs and overall hardly an overly lightweight construction. This one has had a long service life and hasn't suffered any damage apart from punctured tissue from grass landings. AUW 137g - or 4.8oz. This one has gear that I believe would be suitable for a 1/16 guillow's: a 16g, 200g thrust motor, 5g servos and a 460mAh battery. The gear comes in at around 80g total.

[David Lewis]

woundedbear wrote: "David Lewis, But could you clarify this for me. How many grams (or ounces) Per 1 square per inches of wing area? Is this what you mean?"

David Lewis wrote: With Guillow 1/16 scale models, wing area in the 100 sq. in. range, your target gross weight runs between 6 oz. and 12 oz.

[woundedbear]

Thanks for your reply David lewis. I found a video about a device that can be used to slow down a servo's movement.

[Bill Gaylord]

There are numerous differences between your model David, and a Guillows. For a pure flyer, your model is a great example. The minimal contest sheeting doesn't weigh much. It doesn't have numerous, heavy stringers, heavy 1/4" wing main spar and LE stock, and horizontal and vertical fuse keels, as well as fuse formers with considerably less lightening. Tissue is considerably lighter than iron-on coverings, or even painted Microlite. I would imagine most all of the wood is contest or reasonably light wood. The thing to consider is that weight gain tends to be compounding. As the model becomes heavier, the required power system becomes heavier. It all depends on what people want. Some like pure lightweight flyers such as what you have, some like scale sheeting and other details. From what I've been reading, woundedbear strikes me as the type of person who likes something more like this, with scale sheeting, painting, and retracts with steerable/retractable tail wheel. The AUW is 11oz, which I would challenge anyone to build comparably and end up lighter.

[David Lewis]

For anyone who's tackling their first Guillow R/C conversion, the weight goals presented here are realistic. Whether they're desirable is your call. Some people don't mind highly loaded, fast models -- while some people prefer floaters.

If you want to go much lighter you will probably need some experience under your belt, along with a considerable degree of re-engineering, possibly bordering on scratchbuilding which, while I'm personally a big fan, is outside the scope of this thread.