Possible race planes for fun MOM series racing

[smirkracing2024]

I am on-board with a simple racing sailplane design. I was under the impression that the biggest 'pro' of 3d printing was that small-scale manufacturing (sub 100 planes) was still very cost-effective compared to other construction methods.

A fiberglass-fuselage with built-up covered wings etc sounds awesome, but unless someone is already producing that plane, it seems hard to get. Would it be feasible to have one manufactured for our needs?

I think @Wayne has designed, contracted for, and acquired planes and kits more than most, so maybe he can comment on what's feasible.

 

[gnichola]

I’d like to start by stating my bias: I’d love to see a simple racing sailplane with a fiberglass fuselage, wood covered foam wings and simple tail feathers. They have a long history of being relatively robust and repairable. That kind of model seems to be in short supply. It’s pretty clear to me that the 1.5 meter F3F model isn’t an option to solve the need for better robustness. I haven’t reviewed the other two and won’t venture a guess to their suitability. As much as others may love them, flying wings are not my favorite.

I second Ollie's thoughts here, there has to be something in this vein that we can get our hands on.
We have had 3 races so far and we are still only flying 2 up. This will certainly change next year and we will move to the more official 4 up, meaning there will be more POPC (plane on plane contact), which then adds to the need for more durability.

 

[Doc James Hammond]

I’m a sucker for the excitement of a new sailplane as much as the next guy. That said, I’d like to stay focused on what lead us down this path of wonder: we’d like a more robust sailplane for our MoM competition. Let me suggest that the ideal sailplane would have the following three attributes: 1) Robustness, 2) Availability and, finally, 3) Affordability. Aloft and Co. has done a great job on the last two. We went from concept to contest in about two months. Wow! But, the Slingshot, in its current incarnation, isn’t the most robust. There were no available racing sailplanes that solved all three imperatives when we embarked on the MoM event. So, here we are. As they say, “You can’t fly what you don’t have”.

I’d like to start by stating my bias: I’d love to see a simple racing sailplane with a fiberglass fuselage, wood covered foam wings and simple tail feathers. They have a long history of being relatively robust and repairable. That kind of model seems to be in short supply. It’s pretty clear to me that the 1.5 meter F3F model isn’t an option to solve the need for better robustness. I haven’t reviewed the other two and won’t venture a guess to their suitability. As much as others may love them, flying wings are not my favorite.

Let’s not stop the search. Perhaps something will “miraculously” appear over the winter months. Please build 'em, fly 'em, and, "ideally" , crash 'em so we all know they're robust. Doc, I bet with all the sailplanes in your quiver that there MUST be something that can be adapted to suit the occasion .

Ollie

Hey Ollie - I agree wholeheartedly with all of that, but as for my stuff, I have to humbly admit I don't know enough about printing to offer a turnkey design like the Slingshot.

Now, if someone wanted a 3-D design that could be converted to print, that's a different animal. Anyone who has seen my 60: Sessanta, for example, will know that it is fast, but for this type of actual racing (Sessanta is an all-rounder) it could be improved even more - not least by making it joined wings instead of a one-wing design, but in fact an entire revamp including a new airfoil I had developed. A completely new airframe, in fact.

As to the flying wings - yes, I do love them, but I love them from a mechanical point of view because I know that somewhere in that mess of potential design points is a configuration that will be faster than any conventional rear-activated plane - and by the way, that's especially true for F3F. Unfortunately, the ones available and kindly sought out and mentioned by Zeo are far from a good solution.

The problem is finding and developing the right combination and then learning to fly it - flying wings, especially BWB types, are almost like 2d when flying, especially when they're far away and sideways. I have spent time from time to time expanding on the Nurflugel or slope-flying wings thread here on the Aloft Forums.

Again, I'm so happy to see some activity on possible new printed designs. Who is going to be the first to get a new one aloft?...Aloft?

Cheers,

Doc

 

[Roberto Zillante]

I’m probably the Slingshot’s #1 fan! In my experience, its main weak point is the fragility of the fuselage. The wings are fairly tough, especially when using Ollie’s original infill. Apart from that, I think it’s pretty much the perfect plane for MOM racing.

That got me thinking: what about a molded fiberglass fuselage paired with the printed wings and stabilizers?

As some of you know, I’m originally from Venezuela, and a longtime friend of mine, Raúl, runs a small RC glider manufacturing shop there. I actually learned to fly his models as a kid! He builds everything from fully carbon models to fiberglass and sheeted-foam designs. I’m buying one of his molded F3F planes, the Celta, and plan to bring it back after visiting my family this Christmas.

Here’s an example of his work:

Faster Racer 60”

If Ollie is open to the idea (and this is important because is his design), I could ask Raúl about making a fiberglass fuselage for the Slingshot that works with the existing printed components. I think that could address its main weakness while keeping much of what makes the plane so appealing.

A batch of 30–40 fuselages, without stabilizers since those could still be printed, might be reasonably economical to manufacture and ship together. We’d need to check the tooling costs, weight, and final price, but it seems worth exploring. If Wayne is interested, I’d also be happy to introduce him to Raúl to discuss potentially offering them through Aloft.

This is just an idea at this point—I haven’t discussed it with Raúl, Wayne, or Ollie yet. If there’s interest, I’m happy to start those conversations and see what might be possible.

What do you guys think?

Robert.

 

[smirkracing2024]

I’m probably the Slingshot’s #1 fan! In my experience, its main weak point is the fragility of the fuselage. The wings are fairly tough, especially when using Ollie’s original infill. Apart from that, I think it’s pretty much the perfect plane for MOM racing.

That got me thinking: what about a molded fiberglass fuselage paired with the printed wings and stabilizers?

As some of you know, I’m originally from Venezuela, and a longtime friend of mine, Raúl, runs a small RC glider manufacturing shop there. I actually learned to fly his models as a kid! He builds everything from fully carbon models to fiberglass and sheeted-foam designs. I’m buying one of his molded F3F planes, the Celta, and plan to bring it back after visiting my family this Christmas.

Here’s an example of his work:

Faster Racer 60”

If Ollie is open to the idea (and this is important because is his design), I could ask Raúl about making a fiberglass fuselage for the Slingshot that works with the existing printed components. I think that could address its main weakness while keeping much of what makes the plane so appealing.

A batch of 30–40 fuselages, without stabilizers since those could still be printed, might be reasonably economical to manufacture and ship together. We’d need to check the tooling costs, weight, and final price, but it seems worth exploring. If Wayne is interested, I’d also be happy to introduce him to Raúl to discuss potentially offering them through Aloft.

This is just an idea at this point—I haven’t discussed it with Raúl, Wayne, or Ollie yet. If there’s interest, I’m happy to start those conversations and see what might be possible.

What do you guys think?

Robert.

Sounds like an awesome idea to me!!!

 

[Wayne]

Roberto - I've talked with Raúl several years ago about importing his planes, but in the end I was uncertain how well that would work due to some sanctions at the time. Great to see he is still going. His planes looked very tempting. I like that he has a mix of models.

I wonder if he has a fuselage from one of his designs that might fit the bill. Even less expense that way..

I think it is a sound idea.

 

[OribaSJ88]

I’m probably the Slingshot’s #1 fan! In my experience, its main weak point is the fragility of the fuselage. The wings are fairly tough, especially when using Ollie’s original infill. Apart from that, I think it’s pretty much the perfect plane for MOM racing.

That got me thinking: what about a molded fiberglass fuselage paired with the printed wings and stabilizers?

As some of you know, I’m originally from Venezuela, and a longtime friend of mine, Raúl, runs a small RC glider manufacturing shop there. I actually learned to fly his models as a kid! He builds everything from fully carbon models to fiberglass and sheeted-foam designs. I’m buying one of his molded F3F planes, the Celta, and plan to bring it back after visiting my family this Christmas.

Here’s an example of his work:

Faster Racer 60”

If Ollie is open to the idea (and this is important because is his design), I could ask Raúl about making a fiberglass fuselage for the Slingshot that works with the existing printed components. I think that could address its main weakness while keeping much of what makes the plane so appealing.

A batch of 30–40 fuselages, without stabilizers since those could still be printed, might be reasonably economical to manufacture and ship together. We’d need to check the tooling costs, weight, and final price, but it seems worth exploring. If Wayne is interested, I’d also be happy to introduce him to Raúl to discuss potentially offering them through Aloft.

This is just an idea at this point—I haven’t discussed it with Raúl, Wayne, or Ollie yet. If there’s interest, I’m happy to start those conversations and see what might be possible.

What do you guys think?

Robert.

Hola Roberto,

That's a pretty reasonable way of going should he be willing to work with us. We're a rather "price sensitive" clientele for him. But it's definitely worth a chat with him to see if he might be interested. The part of the Slingshot that could most benefit from being made from fiber composites is the part of the fuselage with the wing saddle. Much of the force/torque from a bad landing ultimately has to be resisted within the wing saddle area. The 3D-printed materials just don't have the required strength. The tail boom could be a carbon fiber or fiberglass tube. The servo tray and nosecone could continue to be 3D-printed.

Along the lines of what Wayne suggested, he does seem to offer quite a number of 60" sailplanes with fiberglass fuselages and wood covered foam wings. They seem relatively well-priced although I have no concept of the difficulties of importation. He even has a 60" ODR racer using the requisite SD airfoil. One of those fuselages could easily be adapted to what would have to be a new design for our racing class. Or, adopt one of his designs outright if the price is right .

Ollie

 

[Roberto Zillante]

Roberto - I've talked with Raúl several years ago about importing his planes, but in the end I was uncertain how well that would work due to some sanctions at the time. Great to see he is still going. His planes looked very tempting. I like that he has a mix of models.

I wonder if he has a fuselage from one of his designs that might fit the bill. Even less expense that way..

I think it is a sound idea.

Wayne, small world—I didn’t realize you’d already been in touch with Raúl!


I’d need to confirm the current sanctions and import requirements. I’m honestly unfamiliar with the commercial export process from Venezuela, and corruption at ports and airports can make the logistics unpredictable. That’s why I’m picking up my own plane in person and bringing it back as checked baggage in a hard case I already have.


Ollie, your suggestion of a composite wing saddle section with a carbon or fiberglass tail boom makes a lot of sense, especially if we can keep the nosecone and servo tray printed. I can ask Raúl whether that would be practical and what it might cost.


I’ll also ask about existing fuselages, as both of you suggested. His smallest current models are 60”, so I’m not sure anything would fit the Slingshot directly. But as you pointed out, Ollie, an existing fuselage could be the starting point for a different design—or perhaps one of his complete models could work if the price is right. I have a few of his older models in my garage, so I can take some measurements and photos to see if there’s a promising candidate.


I’ll reach out to him and get a better sense of the options, pricing, and shipping possibilities. Keeping this affordable would definitely be central to the conversation!

 

[Roberto Zillante]

Quick update: I spoke with Raúl, and he’s happy to help! We discussed both options: a fiberglass fuselage for the Slingshot and a simpler, less expensive version of his Faster Racer 60”.


The Slingshot fuselage looks particularly promising. His preliminary estimate is $40–$60 per fuselage, which sounds very affordable to me. He would only need the fuselage STL files, with Ollie’s approval, to print a master, prepare the plug, and make the mold. For a batch of 30–40 fuselages, he would probably make two molds so he could produce them in parallel.


He can paint them in a single color and also offers custom designs, but for a batch like this, keeping to one color or a few standard schemes would help simplify production. We’d still need to confirm what the estimate includes and work out shipping, but it seems like a good starting point.


The simpler Faster Racer is also an option. The current version costs around $280, partly because it’s built for dynamic soaring as well as other demanding flying. Its wings use foam, harder wood sheeting, and fiberglass reinforcement to handle those loads. Raúl thinks a version intended for our MOM racing, using foam and balsa with less reinforcement, could be considerably cheaper. We don’t have a price for that version yet.


The main concern with complete planes would be production capacity. Even with several months available, building 30–40 complete racers could be challenging for his shop, depending on the final quantity and schedule.


Personally, I’m encouraged by the fiberglass Slingshot fuselage option: it could address the weak point we’ve been discussing while letting us keep using the printed wings and tail components.


What do you guys think? Should I keep moving this forward for next year? Would you prefer the fiberglass Slingshot fuselage, or would you rather explore a complete plane based on the Faster Racer, knowing it would cost more and capacity could be a limitation? Raúl is open to helping either way!

 

[zeo0nie1]

Super exciting. His planes look really nice btw.

 

[smirkracing2024]

Quick update: I spoke with Raúl, and he’s happy to help! We discussed both options: a fiberglass fuselage for the Slingshot and a simpler, less expensive version of his Faster Racer 60”.


The Slingshot fuselage looks particularly promising. His preliminary estimate is $40–$60 per fuselage, which sounds very affordable to me. He would only need the fuselage STL files, with Ollie’s approval, to print a master, prepare the plug, and make the mold. For a batch of 30–40 fuselages, he would probably make two molds so he could produce them in parallel.


He can paint them in a single color and also offers custom designs, but for a batch like this, keeping to one color or a few standard schemes would help simplify production. We’d still need to confirm what the estimate includes and work out shipping, but it seems like a good starting point.


The simpler Faster Racer is also an option. The current version costs around $280, partly because it’s built for dynamic soaring as well as other demanding flying. Its wings use foam, harder wood sheeting, and fiberglass reinforcement to handle those loads. Raúl thinks a version intended for our MOM racing, using foam and balsa with less reinforcement, could be considerably cheaper. We don’t have a price for that version yet.


The main concern with complete planes would be production capacity. Even with several months available, building 30–40 complete racers could be challenging for his shop, depending on the final quantity and schedule.


Personally, I’m encouraged by the fiberglass Slingshot fuselage option: it could address the weak point we’ve been discussing while letting us keep using the printed wings and tail components.


What do you guys think? Should I keep moving this forward for next year? Would you prefer the fiberglass Slingshot fuselage, or would you rather explore a complete plane based on the Faster Racer, knowing it would cost more and capacity could be a limitation? Raúl is open to helping either way!

I think both options are promising. Also, I noticed this plane which says it is made for slope pylon racing:

FUN ONE

GALERÍA DE FOTOS Especificaciones: Envergadura: 152.5 cm(60”) Largo: 90 cm (35.5”) Área: 2322 cm2 (360 sq”) Carga alar: 9-12 oz/sq.ft Peso: 24-30 oz (720-900g) Perfil: S6062 9.5% Diseñado por: Raúl…

versaplanes.wordpress.com

Before you and Raul spend too much time perhaps it makes sense to look at how shipping/importing work. I am not sure how much cost will be added, but based on what I see elsewhere (say, ordering from RCFactory, back when that was possible, vs Twisted Hobbys) it looks like total mark-up is in the 35% range. Perhaps @Wayne can (generously) provide a better outcome for this batch of planes.

I expect to crash, particularly if more than 2 people are racing, so I like the idea of an open design, 3d printed wing, since that seems like the piece most likely to be damaged.

 

[OribaSJ88]

Quick update: I spoke with Raúl, and he’s happy to help! We discussed both options: a fiberglass fuselage for the Slingshot and a simpler, less expensive version of his Faster Racer 60”.


The Slingshot fuselage looks particularly promising. His preliminary estimate is $40–$60 per fuselage, which sounds very affordable to me. He would only need the fuselage STL files, with Ollie’s approval, to print a master, prepare the plug, and make the mold. For a batch of 30–40 fuselages, he would probably make two molds so he could produce them in parallel.


He can paint them in a single color and also offers custom designs, but for a batch like this, keeping to one color or a few standard schemes would help simplify production. We’d still need to confirm what the estimate includes and work out shipping, but it seems like a good starting point.


The simpler Faster Racer is also an option. The current version costs around $280, partly because it’s built for dynamic soaring as well as other demanding flying. Its wings use foam, harder wood sheeting, and fiberglass reinforcement to handle those loads. Raúl thinks a version intended for our MOM racing, using foam and balsa with less reinforcement, could be considerably cheaper. We don’t have a price for that version yet.


The main concern with complete planes would be production capacity. Even with several months available, building 30–40 complete racers could be challenging for his shop, depending on the final quantity and schedule.


Personally, I’m encouraged by the fiberglass Slingshot fuselage option: it could address the weak point we’ve been discussing while letting us keep using the printed wings and tail components.


What do you guys think? Should I keep moving this forward for next year? Would you prefer the fiberglass Slingshot fuselage, or would you rather explore a complete plane based on the Faster Racer, knowing it would cost more and capacity could be a limitation? Raúl is open to helping either way!

Hola Roberto,

That's great progress that you've made in your discussions with Raúl. Providing the STL files to him is no problem. However, for a fuselage made from fiberglass, the design would no doubt benefit from changes to accommodate that difference. The tail feathers in particular would likely need some modifications. The nose/nose cone concept should probably be changed/refined for a molded fuselage. Let's definitely keep up the discussion with him, but also let's try to refine the concept to make it as easy as possible for him--and as cheap as possible for us . Perhaps this is something that you and I can discuss in more detail when I'm on travel. We could also arrange a conference call to include Raúl as well.

I second Sumit's, @smirkracing2024, suggestion regarding an in depth investigation into the shipping & importation costs. Venezuela may present some particular challenges given some "events and decisions" that continue to emanate from an address on Pennsylvania Ave . I also looked at the Fun One design in his collection with some interest. Depending on the level of prefabrication, it might be a good candidate for our events. It appears to adhere to the ODR MoM rules used at the Midwest Challenge series. If so, it also might offer the opportunity to open the event to more varied designs.

Ollie

 

[Roberto Zillante]

I think both options are promising. Also, I noticed this plane which says it is made for slope pylon racing:

FUN ONE

GALERÍA DE FOTOS Especificaciones: Envergadura: 152.5 cm(60”) Largo: 90 cm (35.5”) Área: 2322 cm2 (360 sq”) Carga alar: 9-12 oz/sq.ft Peso: 24-30 oz (720-900g) Perfil: S6062 9.5% Diseñado por: Raúl…

versaplanes.wordpress.com

Before you and Raul spend too much time perhaps it makes sense to look at how shipping/importing work. I am not sure how much cost will be added, but based on what I see elsewhere (say, ordering from RCFactory, back when that was possible, vs Twisted Hobbys) it looks like total mark-up is in the 35% range. Perhaps @Wayne can (generously) provide a better outcome for this batch of planes.

I expect to crash, particularly if more than 2 people are racing, so I like the idea of an open design, 3d printed wing, since that seems like the piece most likely to be damaged.

Yes, Sumit, the Fun One is definitely worth considering! I actually own one, and it’s a good racer that’s very easy to fly. Mine is slower than the Slingshot, but I think with the right setup and ballast it could get pretty close. It’s not as fast as the Faster Racer, though.


Raúl actually suggested the Fun One when we discussed something affordable and fun for our group. It’s also a 60” plane, is simpler to manufacture, and costs around $180 before shipping and any import costs.


On the shipping question, he told me he sent a batch of Fun Ones to Kansas just a few weeks ago for a pylon racing event. That’s encouraging and suggests the logistics may be more manageable than I initially thought. I agree with you and Ollie that we should understand the total delivered cost before going much further. I’ll ask him how that shipment worked and what it cost.


The Fun One seems like another appealing option, although I also see the advantage of keeping the Slingshot’s printed wings for easy replacement after a collision!

 

[Roberto Zillante]

Hola Roberto,

That's great progress that you've made in your discussions with Raúl. Providing the STL files to him is no problem. However, for a fuselage made from fiberglass, the design would no doubt benefit from changes to accommodate that difference. The tail feathers in particular would likely need some modifications. The nose/nose cone concept should probably be changed/refined for a molded fuselage. Let's definitely keep up the discussion with him, but also let's try to refine the concept to make it as easy as possible for him--and as cheap as possible for us . Perhaps this is something that you and I can discuss in more detail when I'm on travel. We could also arrange a conference call to include Raúl as well.

I second Sumit's, @smirkracing2024, suggestion regarding an in depth investigation into the shipping & importation costs. Venezuela may present some particular challenges given some "events and decisions" that continue to emanate from an address on Pennsylvania Ave . I also looked at the Fun One design in his collection with some interest. Depending on the level of prefabrication, it might be a good candidate for our events. It appears to adhere to the ODR MoM rules used at the Midwest Challenge series. If so, it also might offer the opportunity to open the event to more varied designs.

Ollie

Thanks, Ollie! I’d be happy to introduce you to Raúl and help arrange a call with the three of us. We can coordinate a time that works while you’re traveling.


I agree that refining the fuselage specifically for fiberglass construction sounds wise. A design that’s easier for him to mold and manufacture should help keep the cost down, too. Perhaps we could incorporate simple mounting points for bolt-on, 3D-printed vertical and horizontal stabilizers? That would also make the tail surfaces easy to replace if damaged.


I’m happy to help keep the conversation moving and work through the details with both of you!

 

[Doc James Hammond]

Wow, looking like this is taking off (Sorry) - wonderful!

It's great to see a lot of "willpower" - instead of "wontpower" developing.

Doc.

 

[Wayne]

I'm not sure, but think the Fun One is based on the One Design Rules. Thus the sales to Kansas as the compete in the ODR class. So if you adopted this ODR design, you actually have a wide range of models people can pick from, or make their own. It has been suggested earlier in this thread.

Shipping and import - This is where things get weird. Sounds like he already has a shipment going to the USA, so should be possible. A quick search suggests either very low tariff, no tariff or simply states our president has made a mess of it all. LOL There are still older restrictions on the country, but that is only if you are doing trade with certain groups or state run operations. Beyond that I'm not sure, most all results are about oil.

I like the Sling Shot wing. A fiberglass fuselage would have the advantage of keeping the airframe cheap, and if import is an issue, you can still print fuselages. I'd suggest dropping the slip off nose cone, built in servo tray, with a lip for the canopy cover. The canopy could remain a printed peace. Thus keeping costs very low. This would simplify the fuselage layup. At the same time I'd look to move the screws further apart in the wing, and leave a dimple in the fuselage for easy drilling. (fuselage would be a top bottom molding so the wing slot does not have a seam in the middle.) Plan for fuselage ballast.

 

[zeo0nie1]

I wonder if printed fuselages can be made stronger by printing them with layer lines going lengthwise? Wouldn't get as nice of curves, but I think it wouldn't matter in terms of flying. Basically, split in half lengthwise, glue together with CF in a channel along the join.

From Sunset last weekend:

 

[Wayne]

Very much so. It is part of the thought process when designing anything printed.

 

[zeo0nie1]

Exactly, but the slingshot and every fuselage that I've printed is oriented in the way shown above

 

[Wayne]

Yes, but the Slingshot has carbon that spans the layers, and ideally that is all glued in.

Span some carbon on the top and bottom and that breakage should occur somewhere else.