Cooling System of the Piaggio PC7: Side-Mounted Forward Radiator
📌 Distinctive Design Features:

投稿日時: 投稿者:
  • Equipped with a water-cooled Isotta Fraschini Asso engine

  • Thin-profile radiators installed on the forward sides of the fuselage

  • The design closely resembles a surface-cooling (film-circulation) system, optimized to minimize aerodynamic drag

  • The radiators are either integrated into the aircraft skin or embedded in such a way that their weight is distributed across the fuselage structure

    🧪 Weight Estimation: Radiator + Oil Tank in the PC7
    Here we re-estimate the internal breakdown of the declared 47 kg, based on design logic similar to that of the Piaggio PC7:
  1. Oil Volume (Prioritizing Cooling Performance)
    • For racing use, maximum cooling efficiency is assumed, with approx. 30 liters of oil on board

    • Specific gravity of aviation engine oil: 0.9 kg/L

    • Oil weight: approx. 27–30 kg

  2. Oil Tank (Aluminum Construction)
    • Located just beneath the engine, mounted forward

    • Capacity around 30L, built from ultra-thin aluminum (≤1.5mm thick)

    • Weight: approx. 3–4 kg

  3. Radiator (Fuselage Side-Mounted)
    • Thin-film structure following the curvature of the fuselage

    • Despite the large surface area, the materials are extremely lightweight (supported by the airframe)

    • Internal piping is ultra-fine, made from brass or aluminum for corrosion resistance and heat dissipation

    • For racing + bonded installation: weight approx. 13–17 kg

      📊 Estimated Breakdown (PC7 Spec)

Component Estimated Weight
Engine Oil (max load) approx. 28–30 kg
Oil Tank (aluminum) approx. 3–4 kg
Radiator (thin side-mounted) approx. 13–15 kg
Total 47 kg
💡 Explanation:
This configuration fits the unique design philosophy of the Piaggio PC7 exceptionally well:

  • Primary cooling is handled by thin-profile radiators exposed to direct airflow

  • Placing the oil tank close to the engine improves circulation efficiency

  • Both the tank and radiator are designed as consumable components integrated into the aircraft’s outer skin, balancing weight reduction with ease of maintenance


🔍 Piaggio PC7 の冷却構造：前方側面ラジエーターの場合

📌 特徴的な設計要素：

  • 水冷エンジン（Isotta Fraschini Asso）を搭載
  • 機体前方の側面に「薄型ラジエーター」を設置
  • 表面冷却型（皮膜循環式）に近く、空気抵抗を最小限に抑えるデザイン
  • ラジエーターは機体の外板と一体化しているか、埋め込み式で重量を機体構造に分担させている

🧪 重量推定：PC7のラジエーター＋オイルタンク

ここでは47 kgという公称重量の中から、Piaggio PC7 のような設計思想に沿って、オイル・タンク・ラジエーターの内訳を再推定してみます：

1. オイル量（冷却を優先）

  • レース用で冷却性能を最大化するため、約30L程度のオイルを搭載と仮定
  • 航空エンジンオイルの比重：0.9 kg/L
  • オイル重量：約27～30 kg

2. オイルタンク（アルミ製）

  • エンジン直下、前方設置
  • 容量30L程度、板厚1.5mm以下の極薄アルミ製
  • 重量：約3～4 kg

3. ラジエーター（機体側面に設置）

  • 側面に沿う薄膜構造
  • 表面積が広くても構造材が非常に軽量（機体が支持）
  • 内部配管は極細で、素材は真鍮またはアルミ（耐腐食・放熱重視）
  • レース用途＋貼付式＝重量：約13～17 kg

📊 推定内訳（PC7仕様）