Conceptual Design Amphibious AI Rescue Aircraft Series (GLARE Trimaran Hull & Battery Electric Prop)

BlueBell said:

So, you are designing to an aesthetic, that is not sound engineering in my humble opinion.

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The products we design must meet a range of technical requirements, but they must also have an attractive appearance. In every design office for ships, airplanes, or cars, there are industrial designers who sketch a series of concepts during initial development for the day the project is presented to a committee for approval.
Rabah

Rabah said:

In every design office for ships, airplanes, or cars, there are industrial designers who sketch a series of concepts during initial development for the day the project is presented to a committee for approval.

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Not quite. In general most designs start with an statement of requirements (SOR), and some kind of decision matrix. The pretty drawings are for the marketing department.

gonzo said:

Not quite. In general most designs start with an statement of requirements (SOR), and some kind of decision matrix. The pretty drawings are for the marketing department.

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I have always liked well-streamlined designs. Only in military shipbuilding do you find angular structures with sharp bends in the superstructures and deckhouses, which is because of the enemy's radar systems; however, the main hull remains perfectly streamlined.But when it comes to planing hulls—such as cutter bottoms with transverse or longitudinal steps—the situation is completely different.
Rabah

Rabah said:

The products we design must meet a range of technical requirements, but they must also have an attractive appearance. In every design office for ships, airplanes, or cars, there are industrial designers who sketch a series of concepts during initial development for the day the project is presented to a committee for approval.
Rabah

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It sounded like you were emotionally attached to the aesthetic, trying to "reverse engineer" it into an SOR. Again, not sound engineering.
It causes unnecessary compromises that take away from the SOR.

Not sure why a commercial venture would be looking to a forum for direction.
It lacks professionalism and confidence.
Who am I to judge.
Carry on.

BlueBell said:

It sounded like you were emotionally attached to the aesthetic, trying to "reverse engineer" it into an SOR. Again, not sound engineering.
It causes unnecessary compromises that take away from the SOR.

Not sure why a commercial venture would be looking to a forum for direction.
It lacks professionalism and confidence.
Who am I to judge.
Carry on.

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Dear Blue Bell,
If our design seems abnormal to you, why do you even bother commenting on it? You call my idea a 'redesign,' but I absolutely disagree with that! Mr. Alan Canamar designed his trimaran structure with specific overall dimensions and according to his own technical specifications. Our design has completely different dimensions and a totally different purpose (meaning the specifications are fundamentally different from what Canamar set out to do). The only thing they share is the aircraft classification: an amphibious seaplane capable of landing on both land and water. This is like accusing someone of 'redesigning' something just because it was created before them. It only shows that you are unfamiliar with design methodologies.
Let's take shipbuilding as an example: Before starting work on the preliminary, pre-design phase of a new ship, a data table is compiled with information on prototypes of similar dimensions and the same type—such as a tanker or a bulk carrier, etc. This by no means implies that the design organization is stealing ideas. And why are you annoyed by the fact that a good designer is not truly a good designer if they do not strive for their structure to have a perfect and beautiful appearance? No one designs a new ship without reviewing at least a dozen silhouettes (side-view sketches above the waterline). Therefore, I believe you are not well-acquainted with the subtleties of the design process.
Of course, I could have given you a very brief answer: Everyone chooses their own way of designing a new product, especially when money is involved—whether it is for creating a scale model prototype or for developing pre-design technical documentation.
I need this forum because I am a shipbuilding engineer, not an aerospace engineer. The debates here help me understand if there are any flaws in the structure. The main challenge is whether it will successfully lift off the water after planing, and crucially, at what speed and power. For such matters, I would never rely entirely and solely on AI.
Sincerely,
Rabah

The wings look to be very close to the water, closer than in any seaplane I ever saw except wing in ground effect craft (and at least one of those has high wings). I think that raises a few questions:
1) Keeping in mind that waves are not a constant height along their crests, and that more than one wave pattern may cross, so you can't rely on just heading into the waves, what can the sea state be before waves slam into the underside of the wings?
2) Does building to slamming loads change the weight of the craft?
3) If the structure can be built to cope with slamming loads, what will the slamming do to crew and casualties?
4) How much does the craft get pulled off course when it dips in just one wing tip?
5) Given the statistics on sea states and calls for help in the intended area of operation, what proportion of calls would you have to ignore because the craft can't safely touch down or take off? How does that compare to alternative designs?
6) If you want to rely on greater range compared to some alternatives, how much would it cost to save one quality-adjusted life year (Quality-adjusted life year - Wikipedia https://en.wikipedia.org/wiki/Quality-adjusted_life_year) with your design compared to others?

Rabah said:

If our design seems abnormal to you, why do you even bother commenting on it?

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You ask for comments. The design seems abnormal because it does not fulfill the requirements you have.

Rabah said:

I need this forum because I am a shipbuilding engineer, not an aerospace engineer.

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That is obvious. However, you are unwilling to learn. Instead you are defending a design that is based on aesthetics. Further, if you are a shipbuilding engineer, starting with an SOR should be the logical first step.

Rabah said:

If our design seems abnormal to you

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I never said, nor do I believe, it seems abnormal.

Rabah said:

why do you even bother commenting on it?

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I am starting to question that myself.

Rabah said:

You call my idea a 'redesign,'

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I did not call your idea a redesign.

Rabah said:

And why are you annoyed by the fact that a good designer is not truly a good designer if they do not strive for their structure to have a perfect and beautiful appearance?

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I am not annoyed. You seem confused.

Rabah said:

The main challenge is whether it will successfully lift off the water after planing

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This should not be the main challenge.

Rabah said:

I need this forum because I am a shipbuilding engineer, not an aerospace engineer

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This is not an aerospace forum.


Sadly, you have completely missed my point, as simple as it was.

Best of luck to you my friend, you're going to need it.

Robert Biegler said:

The wings look to be very close to the water, closer than in any seaplane I ever saw except wing in ground effect craft (and at least one of those has high wings). I think that raises a few questions:
1) Keeping in mind that waves are not a constant height along their crests, and that more than one wave pattern may cross, so you can't rely on just heading into the waves, what can the sea state be before waves slam into the underside of the wings?
2) Does building to slamming loads change the weight of the craft?
3) If the structure can be built to cope with slamming loads, what will the slamming do to crew and casualties?
4) How much does the craft get pulled off course when it dips in just one wing tip?
5) Given the statistics on sea states and calls for help in the intended area of operation, what proportion of calls would you have to ignore because the craft can't safely touch down or take off? How does that compare to alternative designs?
6) If you want to rely on greater range compared to some alternatives, how much would it cost to save one quality-adjusted life year (Quality-adjusted life year - Wikipedia https://en.wikipedia.org/wiki/Quality-adjusted_life_year) with your design compared to others?

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Hello,
I consider all 6 of your questions to be extremely important. Before answering them specifically, I would like to clarify the context of the project and its evolution.

1. Design Philosophy and Transition to a Humanitarian Mission
Initially, I started the project using the "Method of Similitude" . This approach allows not only for geometric similarity in overall dimensions but also for consistency in hydrostatic, hydrodynamic, and aerodynamic performance between Alan Canamar's prototype (with a maximum length of about 14 meters) and our 5 proposed models.
However, during the design process, it became clear that an independent designer cannot compete with large corporations. They possess vast resources for preliminary designs aimed at the Navy, which will naturally look for multiple bids from established companies. Therefore, I shifted the focus of the project toward its humanitarian value — emergency medical services (EMS) in scaled-down dimensions. The concept was reformulated as "Small Amphibious Aircraft for Emergency Medical Services". This change resonated very well with the community on Boat Design.net, as evidenced by the high view count of the thread.

2. Technical Calculations and Deviations from the Method of Similitude
The design is progressing, and a significant volume of calculations beyond pure hydrostatics is scheduled. These include:

• Total required power at maximum payload.
• Accelerations during rolling in heavy seas (taking into account the design wave height for the specific operating region).
• Bow slamming loads (impact forces on the hull), followed by calculations for global and local strength.

Practice has shown that the method of similitude cannot be blindly applied to all three axes. While this is possible along the X and Y axes, a deliberate deviation was necessary along the Z-axis (height). In a real-world scenario, the medical professional cannot remain seated throughout the entire return flight — they must tend to the casualties, which requires at least a hunched or stooped position. For this reason, I adopted an overall height of 1.6 meters for our first model, whereas Alan Canamar's prototype has an overall height of 2.4 meters.

3. Specific Answers to Your Questions:

• Regarding Question No. 4 (Wingtip Dipping): The control concept and design do not anticipate the aircraft banking to such a degree that a wingtip touches the water during touchdown. Piloting must be highly precise, and the landing itself must be transversely stabilized by the spaced-out floats, without any heel. A small trim is of no significant consequence to stability at that moment.
• Regarding Question No. 5 (Comparison with Alternative Designs): At this stage, it is too early for a comparative analysis. Detailed comparisons with other concepts can only be made after the preliminary design of our first model, KAST 1, is fully completed.
• Regarding Question No. 6 (Cost per Quality-Adjusted Life Year - QALY): At the moment, I do not have the necessary economic and operational data to provide a well-founded answer.

Sincerely, Rabah
21.10.2026

Rabah said:

Practice has shown that the method of similitude cannot be blindly applied to all three axes. While this is possible along the X and Y axes, a deliberate deviation was necessary along the Z-axis (height).

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It can't be applied to the Y axis either because a flying wing does not have a tail. The method of similitude is not applicable, which is what everyone is telling you. This is a completely new design that has to start with an SOR and based on first principles.

Rabah said:

• Regarding Question No. 4 (Wingtip Dipping): The control concept and design do not anticipate the aircraft banking to such a degree that a wingtip touches the water during touchdown. Piloting must be highly precise, and the landing itself must be transversely stabilized by the spaced-out floats, without any heel. A small trim is of no significant consequence to stability at that moment.
• Regarding Question No. 5 (Comparison with Alternative Designs): At this stage, it is too early for a comparative analysis. Detailed comparisons with other concepts can only be made after the preliminary design of our first model, KAST 1, is fully completed.
• Regarding Question No. 6 (Cost per Quality-Adjusted Life Year - QALY): At the moment, I do not have the necessary economic and operational data to provide a well-founded answer.

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I did not think a pilot would bank at low altitude. I am saying that even in perfectly level flight, the lower the wings, the tamer the sea state that can lead a wingtip to dip in. Also, the lower the wing, the more likely it is to slam. By committing to a wing that low, you seem to be inviting two problems without any compensating benefit that I can remember you mentioning.

If wingtip dipping and wing slamming must be avoided, that restricts the operating conditions in ways that you should be able to quantify before you have settled on all the design details. There will be a sea state above which the craft can't safely touch down or take off. Given statistics on sea state and calls for help, you should be able to estimate which proportion of calls your craft must ignore.

BlueBell said:

I never said, nor do I believe, it seems abnormal.

I am starting to question that myself.

I did not call your idea a redesign.

I am not annoyed. You seem confused.

This should not be the main challenge.

This is not an aerospace forum.


Sadly, you have completely missed my point, as simple as it was.

Best of luck to you my friend, you're going to need it.

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Dear Blue Bell,
My replies are based on the built-in translation function of this forum. I will address your points in reverse order.
First of all, I am not your friend. Secondly, I do indeed need success—that is the only thing you got right. I do not like people who speak in riddles and veiled thoughts. As an engineer, I prefer to speak the language of numbers—clearly and precisely. Do not try to take back your words about "abnormal design" and "redesign". It is impossible for the forum's translators to make such massive errors. I am not confused at all! Tomorrow you will probably deny having said these words as well. I am simply reserved about your comments, which are allegedly made with good intentions. I have encountered such people in other forums before; their real goal is to sow doubt and undermine the confidence of other readers in a new idea.
Both you and gonzo actively push the idea that before starting my project, I must absolutely conduct a Statement of Requirements (SOR) study first. I hope you both see what is happening in the world. I do not need such a study right now. Every day on the TV news, I see the brutal war in Ukraine, gutted apartment blocks, and mutilated people in need of help. Close to Bulgaria's borders, there are already two damaged ships in the Black Sea, struck by military drones. I will not waste my time debating whether my idea will help people in distress or not!
That is why I believe I must use my own calculations to verify all preliminary estimates of the experimental model provided by the GOOGLE AI search engine across all speed ranges, including the take-off speed after planing. This needs to be done for all 5 models that we are presenting to the readers. Alan Canamar used Solidworks, but I do not have it. I will rely solely on Maxsurf, where the trimaran hull configuration is specified as a vessel type.
Your comment that this is not an aerospace forum should be directed to the forum moderators, not to me, as there is a specific section here named "Hydrodynamics and Aerodynamics". Why do you think aerodynamics should only apply to the sails of sailing yachts, but not to a hydroplane with a trimaran construction? Regarding the translation of your supposedly precise words, you should also contact the forum moderators!
Rabah
22.10.2026

Robert Biegler said:

I did not think a pilot would bank at low altitude. I am saying that even in perfectly level flight, the lower the wings, the tamer the sea state that can lead a wingtip to dip in. Also, the lower the wing, the more likely it is to slam. By committing to a wing that low, you seem to be inviting two problems without any compensating benefit that I can remember you mentioning.

If wingtip dipping and wing slamming must be avoided, that restricts the operating conditions in ways that you should be able to quantify before you have settled on all the design details. There will be a sea state above which the craft can't safely touch down or take off. Given statistics on sea state and calls for help, you should be able to estimate which proportion of calls your craft must ignore.

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If there is a heavy sea state, the craft simply will not touch down directly in the disaster zone. Instead, it can land in a more sheltered area, such as on the shore itself or within a protected estuary/lagoon.
I have already commented on this issue before. Initially, the "heavy artillery" is sent to the disaster zone—meaning Navy SEALs or rescue teams in large helicopters, who deploy inflatable boats and winch lines. These rescue teams will secure the people in distress and transport them to the safely landed amphibian aircraft. The amphibian's role is purely medical, though it also has the capability to carry small medical rescue drones. These drones can be operated by the doctor on board the amphibian, who must also be certified to pilot such drones.
A question for Robert: Why should we even consider landing in a severe sea state in the first place? We will clearly specify the operating limits and exact sea areas for which the craft is designed and calculated!
Rabah
22.10.2026

gonzo said:

It can't be applied to the Y axis either because a flying wing does not have a tail. The method of similitude is not applicable, which is what everyone is telling you. This is a completely new design that has to start with an SOR and based on first principles.

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Dear gonzo,
In my response to Blue Bell, I have already explained why there is currently no need for me to conduct a study on the necessity of such amphibious emergency medical service (EMS) aircraft.
Your question would be more appropriate if it were formulated in the following way: not whether they are necessary, but how many units should be built for the specific rescue service! However, an answer to this question is only possible after the construction of the first experimental prototype and, most importantly, after its successful testing.
Regarding the application of the "Method of Similitude," you are only partially correct about the Y-axis.
Alan Canamar's prototype has a fuselage width (the main hull of the aircraft's trimaran configuration) of 2.61m.
I needed the similitude to understand exactly where along the length of the first KAST 1 model to design a transverse step, which strongly affects the planing regime for quickly overcoming the peak of the water resistance curve.
I managed to achieve similitude along the X-axis.
Initially, for the Y-axis similitude, I had assumed a fuselage width of 1.30m, but subsequently, I increased this value to 1.60m due to design considerations—to arrange the two seats side-by-side rather than tandem (one behind the other), and also to provide greater operational space for the medical professional attending to the casualties on the stretchers.
Rabah 23.10.2026

Rabah said:

If there is a heavy sea state, the craft simply will not touch down directly in the disaster zone. Instead, it can land in a more sheltered area, such as on the shore itself or within a protected estuary/lagoon.
I have already commented on this issue before. Initially, the "heavy artillery" is sent to the disaster zone—meaning Navy SEALs or rescue teams in large helicopters, who deploy inflatable boats and winch lines. These rescue teams will secure the people in distress and transport them to the safely landed amphibian aircraft. The amphibian's role is purely medical, though it also has the capability to carry small medical rescue drones. These drones can be operated by the doctor on board the amphibian, who must also be certified to pilot such drones.

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That makes it harder for me to understand what advantage your craft offers. If helicopters pick up casualties, why transfer them? Every transfer is a risk. Every transfer takes time and fuel while the helicopter hovers. If you intend your craft to offer medical equipment and services that a helicopter doesn't, what makes it more capable of carrying that load? If you intend your craft to offer faster transport than the helicopter, then any time saved that way has to be offset against the time taken to transfer, and the time needed to transfer from where your craft lands to a hospital. If the hospital has a helipad, the helicopter doesn't need that transfer, and would save a total of two transfers, from the helicopter to your craft, and from your craft to an ambulance.

Even if your craft is faster than a helicopter, the further away your craft must be from where the casualties are picked up, the less time it can save. If you craft can carry equipment that a helicopter can't (though then it could be more cost-effective to fly larger helicopters rather than combine small ones with your craft), the longer it takes to get to your craft the less advantage there is compared to going directly to a hospital.

Rabah said:

A question for Robert: Why should we even consider landing in a severe sea state in the first place? We will clearly specify the operating limits and exact sea areas for which the craft is designed and calculated!
Rabah
22.10.2026

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I originally thought you wanted to pick up casualties directly. If you expect to rely on helicopters for the initial pickup, then see above. To the extent that you want to pick up casualties directly, an example could be illustrative.

What matters is not the distribution of sea states over time, but the distribution of casualties over sea states. Some casualties can occur in glassy calm seas, but rough seas will make them more common due to falls and equipment failure, up to sinking. Lacking statistics, I will make up some numbers, which you can adjust if you have data for your intended operating area.

Using the WMO sea state code (Sea state - Wikipedia https://en.wikipedia.org/wiki/Sea_state#WMO_sea_state_code), let's say casualties are distributed as follows:
Sea state 0: 2
Sea state 1: 3
Sea state 2: 5
Sea state 3: 8
Sea state 4: 12
Sea state 5: 18
Sea state 6: 22
Sea state 7: 16
Sea state 8: 8
Sea state 9: 6

In so far as I can judge from a few videos, rescue swimmer from helicopters can pick people up from the water up to sea state 7, so within their range, they could pick up 86 out of the 100 casualties above. If your craft can only touch down up to sea state 2, then your craft can directly pick up 10 out of 100 casualties, provided they are in the sea. If there were a medical emergency on a ship in glassy calm sea, helicopter could pick up directly from the ship, while your craft would need the casualty to be lowered down. How many ships are equipped for that?

Generally, fixed wing aircraft offer greater speed and fuel efficiency than helicopters. Using batteries with their lower energy densities at least reduces that advantage.

In summary, it is not clear to me what your craft offers to search and rescue services that would make it worth the expense. Apparently, they need helicopters anyway. Assuming a fixed budget, the rescue service would have to reduce the number of helicopters and reassign personnel to your craft, which would be more sensitive to sea state simply because it has to touch down, and the low wing makes it more sensitive. Given that reduction in the number of helicopters and rescue swimmers, which you need for the initial pickup, how does your craft help?