Forza 2.5

[JJ Colorado]

Thanks for the CG suggestions. I'll figure it out. When it comes to fine tuning CG I rely on the old adage..

A plane with a CG too far forward flies poorly.
A plane with a CG too far back flies once.

 

[Doc J]

Thanks for the CG suggestions. I'll figure it out. When it comes to fine tuning CG I rely on the old adage..

A plane with a CG too far forward flies poorly.
A plane with a CG too far back flies once.

Yep, all true, JJ and Jonty.

My problem is always the same. I can control the model design and manufacture so as to make a viable and fun flying machine, but I cant control who buys them. I once got a badly broken hand from being hit by a plane - a fully moulded 4m scale model - "flown" (for about 3 seconds) by a gent who had never flown anything before in his life.

When I asked him, not very politely, why he thought he could fly such an advanced and expensive model with no flying experience, he replied: (Translated from Mandarin Chinese) "Bloke in the model shop - in Dusseldorf - told me anyone could fly it..." Added to that, many people really do overestimate thier flying proficiency.

Thats why I refuse to make DS models.

Writing the flying set up bits in the instructions is at best only advice. You have to try to cater to all levels of experience, which of course is impossible. I dont know if you have ever had anyone (Even an experienced flyer) hand you a transmitter on the slope, and you take over flying - and almost imediately wonder how the heck he flies on these settings?

The only way is to go conservative, in the hope - mostly justified - that the buyer will know that the advised start positions will be safe but not optimal. In the end its the flyers own settings that count, and if the CG is in the right place (for him) then all the controls will talk to each other very nicely.

No doubt Jonty, as a highy experienced flyer, has honed his personal settings down to fractions of a millimetre.
JJ is the same and its only time before he gets his plane flying on the dendritic edge.

The only thing I will say for the Forza - Check your pacemaker battery before flight if you do get it right...Maybe I should put that in the instructions...

Cheers,

Doc.

 

[JJ Colorado]

CG is a Very subjective matter, for proficient pilots. Each different flying discipline has its own special needs. For F5J or 2MRES I tend to like a very aft CG, but not so far back as to make the plane twitchy or prone to tip stalls. You need to be confident in cranking a tight thermal without fear of an unanticipated snap roll. For the most part I prefer small elevator movements as that provides aerodynamic efficiency, but all of that is lost if you don't feel completely confident, and relaxed flying your model. You fly best when the flying is thoughtless, and effortless as you can focus on the air, not how your airplane handles.

So you want to know the range. A = unstable, B = novice or first flight forward CG, C = suggested CG. With that you begin your process with that plane, and for how you plan to fly it. Perhaps a new CG rating standard should be established. Three numbers: Unstable, Lawn Dart, Reasonable. Take it from there and do what you will, based on your skill and preferences. BTW, the CG value I am most interested in is "Unstable" as that is what I use for determining nose weight.

Slopers are a bit more difficult as you really have a range of CG values based on wind speed, turbulence and load factors. What works well unballasted on a light wind day might be too aft for a strong gusty day when you ballast up. For the Forza my Ballast tube mid point is at 95mm, with the assumption that when adding ballast I'll want that to move the CG very slightly forward. I can alternate loaded and empty ballast slugs if needed, and probably will to fine tune my CG preference.

The most difficult CG to set is for plank type planes. I've got many of those and my Moth is a prime example. It flies wonderfully, fast and agile. The CG is set where I like it.

 

[Hill Hobbit]

Hi JJ, how’s It going with the Forza?

 

[JJ Colorado]

Hi JJ, how’s It going with the Forza?

Fuse is done other than nose ballast but stalled on the wings for a little while longer. Decided to order some ball bearing supported frames for the Mini X10 flap servos and the only place that had them in stock is not shipping until next week. Not every servo needs BB support but seems like the flaps on this one might benefit from that.

I could use some advice though. On my F5J models I use deans connectors and they glue in pretty nicely. The 6 pin MPX connectors are a snug fit in the fuse, but there is not a lot there to glue them in to. Any advice or technique to get them lined up and secured strongly in the fuse?
My plan is to open the holes for a snug fit then simply epoxy them in, but I'm concerned there isn't a lot of material for the epoxy to bond to. ???

 

[Konrad]

Sorry Wayne this was meant to be a PM

 

[Hill Hobbit]

Hi JJ, I always use the connector half in the pic with the white fuz on my installs to the fuz. I’ve always made the rectangular hole so the connector is a snug fit, then I file a chamfer on all 4 sides to accept an epoxy fillet. I degrease the connector, then tack it in the right position with cyano applied with a very small wire (or pin) dipped into a blob of cyano. I then use slightly thickened epoxy to fill the chamfers all around the connector. I have never had a connector come loose and get pushed in or pulled out.
The wing harness connectors I leave loose, which is as most folks do. I do have a CCM Toy which has the wing harness connectors glued into the wing roots, but given the choice, I wouldn’t have done that myself.

 

[JJ Colorado]

Thanks for the feedback and info on your fastening technique. I used to glue both sides for my F5J planes but now I am swapping out joiners with different angles depending on conditoins so I always leave the outside connector free. When you see the flex that some wings go through it seems to make sense not to make angles fixed at both sides.
I might try to provide some extra backing behind the connector but perhaps that is over building for this type of component.

 

[Hill Hobbit]

JJ, there’s no need whatsoever for any ’overbuilding’ as you put it.

 

[Doc J]

Hi JJ, I always use the connector half in the pic with the white fuz on my installs to the fuz. I’ve always made the rectangular hole so the connector is a snug fit, then I file a chamfer on all 4 sides to accept an epoxy fillet. I degrease the connector, then tack it in the right position with cyano applied with a very small wire (or pin) dipped into a blob of cyano. I then use slightly thickened epoxy to fill the chamfers all around the connector. I have never had a connector come loose and get pushed in or pulled out.
The wing harness connectors I leave loose, which is as most folks do. I do have a CCM Toy which has the wing harness connectors glued into the wing roots, but given the choice, I wouldn’t have done that myself.

Exactly as I do it.

Doc.

 

[Hill Hobbit]

This is an example of how Doc J and I (and many others) mount MPX connectors to a fuz:

 

[Doc J]

This is an example of how Doc J and I (and many others) mount MPX connectors to a fuz:

Yep.

You can try to make them "plug in" where they are fixed and automatically connect each side but its really sketchy.

Doc.

 

[JJ Colorado]

This is an example of how Doc J and I (and many others) mount MPX connectors to a fuz:

I've done that for my Forza and just went with epoxy for the Magnus. My fillet is a little smaller but all the connections seem to be fairly strong.

Next decision, how to dress the harness wires on the Forza. Magnus routing worked out nicely. But they both should work out well.

BTW the main Forza ballast is 370 grams in the fuse ballast tube, with 345 grams in the wings. Should be more than enough IMO.

 

[JJ Colorado]

Forza almost completed. Just need to put on servo hatches, add a little more nose weight, and program the radio. It is heavier than I expected at roughly 2100 grams ready to fly.

I used Liu's hardware and while I really like the solid engagement and 1.8mm pins, the C clips are a bit of a pain to work with. Most importantly for this model the extra size of the clevis ends required a fair amount of opening the slots to reduce binding. Not a huge deal, but it always pains me a little when I need to enlarge holes in the wing surface. But given the size of the surfaces having the larger pins in the control horns should minimize any linkage play. Control throws are good in general, though I can't get the flaps more than 70-75 degrees of down. I believe that should be sufficient to slow it down for landing. A few servo linkage pics attached along with my translucent yogurt containter elevator servo cover in place. Will likely replace that with the stock cover after some test flights, but I do like being able to see control linkages without needing to remove hatches.

 

[Hill Hobbit]

70/75 degrees with that amount of servo offset, something strange there. 90 degrees is available on mine, but I really use say 85 when needed to stop it dead or go backwards when hovering down. We can’t usually ‘fly‘ any sloper in on our local sites to avoid overflying footpaths and walkers.

 

[Hill Hobbit]

If your flap was actually not at neutral in your pic of the servo, sorry, my bad!

 

[Doc J]

Forza almost completed. Just need to put on servo hatches, add a little more nose weight, and program the radio. It is heavier than I expected at roughly 2100 grams ready to fly.

I used Liu's hardware and while I really like the solid engagement and 1.8mm pins, the C clips are a bit of a pain to work with. Most importantly for this model the extra size of the clevis ends required a fair amount of opening the slots to reduce binding. Not a huge deal, but it always pains me a little when I need to enlarge holes in the wing surface. But given the size of the surfaces having the larger pins in the control horns should minimize any linkage play. Control throws are good in general, though I can't get the flaps more than 70-75 degrees of down. I believe that should be sufficient to slow it down for landing. A few servo linkage pics attached along with my translucent yogurt containter elevator servo cover in place. Will likely replace that with the stock cover after some test flights, but I do like being able to see control linkages without needing to remove hatches.

JJ you mght want to reduce the elevator compensation to 5.5 or 5mm (from 6mm) for crow landing with 75 degrees of droop. Normally with the flaps fully deployed it will just park motionless in good air. Makes for great front of slope landings.

Good luck with the maiden.

Cheers,

Doc.

 

[JJ Colorado]

Forza is finished other than minor radio tweaks. A bit heavier than I had hoped but still be reasonable.

Base weight 2142gr CG 103
One nose wt 2155gr CG 101 15oz/sq ft wing loading
Two nose wt 2168gr CG 99.5 likely test flight CG
Ballast tube loaded + one nose wt 2562gr CG 100.3 looks like my ballast tube position is good.
Ballast tube + wing wt + one nose wt 2870gr CG 98.1 20oz/sq ft wing loading

As noted, my plan is for a test flight at the 99.5 CG at first then remove nose wt after getting the radio trims and throws dialed in a bit. Any comments on weight, wing loading or CG as compared to other Forzas appreciated. Probably going to be two to three weeks before the maiden flight. BTW it looks great. Need to find a grassy LZ and some decent wind.

 

[Doc J]

Forza is finished other than minor radio tweaks. A bit heavier than I had hoped but still be reasonable.

Base weight 2142gr CG 103
One nose wt 2155gr CG 101 15oz/sq ft wing loading
Two nose wt 2168gr CG 99.5 likely test flight CG
Ballast tube loaded + one nose wt 2562gr CG 100.3 looks like my ballast tube position is good.
Ballast tube + wing wt + one nose wt 2870gr CG 98.1 20oz/sq ft wing loading

As noted, my plan is for a test flight at the 99.5 CG at first then remove nose wt after getting the radio trims and throws dialed in a bit. Any comments on weight, wing loading or CG as compared to other Forzas appreciated. Probably going to be two to three weeks before the maiden flight. BTW it looks great. Need to find a grassy LZ and some decent wind.

Hi JJ - I would ask Jonty (Hill Hobbit) to confirm the CG and especially the control specs you want to use beforre chucking it off a cliff.

Jonty probably has more experience with the Forza than anyone else on the planet, and apart from being a nice chap, he's a demon pilot to boot.

Cheers,

Doc.

 

[Doc J]

Here is a video of the Stormbird which was the forerunner to the Forza flying at Manilla slope fest in Australia in 2018.The model is the same as the Forza in most respects except for th smaller 2m wing span and some changes to the servo mounting system.